1. Brainstorm
No real surprises here. Everyone loves a Brainstorm and knows its power. As stated before, it is one of the most options per mana you can get from a card. With a full hand it is off the charts and even with an empty one you have six ways of doing things. It is instant, it is card neutral, it is cheap as chips and it is one of the most abusable card quality effects. It is one of very few cards in magic which let you transfer cards from hand to the library which has a vast array of good applications too. Combine it with a shuffle effect and you have even more card quality. Brainstorm gives you far more momentum in your options than the alternatives as well. You get three brand new cards, potentially all in your hand and all able to be used right away. Most other card quality effects give you one new card right away and/or afford quality of draws in subsequent turns but Brainstorm offers its action right away. A word of warning however. The best card quality spell this might be but it is also the card I see misused most. This is unsurprising as it is so complicated and full of options but it is still very noticeable. So many people blow it as soon as they can which is usually wrong. Because of the immediacy of Brainstorm as well as the benefits of combining it with cards like sac lands it is usually correct to hold onto a Brainstorm until you need to use it. The turn you need to dig for that answer or land. I also see people playing Brainstorm in decks where alternatives would be better. Unless you have lots of shuffle or a particular synergy with the Brainstorm such as miracles you are usually better off with a more self contained effect. You can't often keep one land hands with Brainstorm because without shuffle you will be doomed to drawing the non lands cards you put back. I frequently find I play Opt over Brainstorm in simple control decks. Brainstorm is a little bit of immediate general and specific card quality but without something to combine it with that quality is lost over the course of the next two draws. Most of the alternatives on this list offer better general or better specific card quality and so you really need to know what it is you are trying to do with this kind of spell so as to play the most effective in your deck. Brainstorm is for abuses, synergy and very specific roles, without these just play Opts, Tutors and Preordains.
2. Sensei's Divining Top
Another unsurprising card at the top end of the list the Divining Top is a known powerhouse. It suffers many of the same faults as Brainstorm in that is is often over complicated and can sometimes do basically nothing. Should you not have other ways to manipulate the library it is far harder to milk any advantage out of Divining Top. That is about the only criticism I have of the card, that and it is boring to play against because it takes so damn long to do it properly. The card is cheap, a great mana sink, near unkillable, offers ongoing card quality and is able to do so for any colour. It offers a wide array of synergies simply by being a cheap artifact. It is weaker at smoothing out your curve as it doesn't really filter cards without shuffle and despite being cheap it is still twice as much to lay and use a Top than it is to Preordain. Top more than makes up for this by being an ongoing source of card quality. It is the best card to combine with miracles as you can both set up the miracle and then draw it in your opponents turn for no extra mana. The same warning applies that unless you have synergy or abuses you should be playing something simpler and ultimately more effective.
3. Scry Lands (The Temples)
Subtle but amazing. Going Island Opt is much the same as making a scry land. Unless you want to leave up mana and are mono coloured the scry land is unequivocally better. It gives two colours of mana next turn and gives you the scry with one extra card in hands worth of information so that you can make a better call. Scry lands do kind of force you into using them as they are also your land drop but mostly that is best because you want your card quality early. The really amazing thing about scry lands is that they offer every colour a little bit of card quality. Not long ago you pretty much had to be blue for those cheap convenient card quality effects but now you just throw in some temples and your deck is that much smoother for it. They have made non-blue midrange and control decks that much easier to build. The blue ones didn't get any worse for them either! I consider these to still qualify for the list despite the fact they are clearly getting used most as lands that tap for mana. The point is that you play these instead of other lands that are usually better duals or even basics simply for the scry. To my mind that is the same as playing something only for its card quality offerings. Going turn one scry land is one of the best openers in cube these days, short of a Goblin Guide level one drop, it is what you want to be doing. The ongoing effect of that early bit of filtering is immense and has made magic a significantly better game as a result.
4. Lat-Nam's Legacy
The poor mans Brainstorm but at least it has a built in shuffle and is therefore a self contained piece of general card quality. Compared to Brainstorm it gives you the cards slower, costs twice as much and it one less new card in hand and one less old card shuffled away. This is a lot to pay for a built in shuffle but due to the power of putting cards in hand back in the library the Legacy sees a vast amount of play and remains one of the best card quality cube cards. If you play it how it reads you can also make it a draw two when you have no cards in hand. It has some added utility at evading discard effects. Instant is fantastic and on the pricier card quality spells (yes, two is pricey for card quality!) is that much more important. Lat-Nam's is more the kind of card you play when you have specific uses than it is one you play to smooth out your early draw. It is better at getting you out of a screw than Top or a Brainstorm but it is painfully slow to do so compared with something more humble like a Preordain. If you have a card that is key to your plan but something you want to use late and need to protect early such as an Elixir of Immortality then Lat-Nam's is a great call. It is almost an auto include in any deck with miracles as it makes you much less susceptible to mulligans. The more shuffle away effects you have the more you are able to keep hands containing miracles.
5. Impulse
Another undervalued card and one I go in to far more depth about in the previous article. It is cheap enough given that it is instant and does an awful lot. It digs deeper than most card quality while affording a lot more ongoing information than the others as well. It also does this without the risk of clogging up your upcoming draws with things you don't want which a lot of the effects can lead to (Brainstorm, Ponder, Scroll Rack or any misplayed scry!). If you are after a specific thing this is better than most due to how deep it digs and if you are just after a land then it gives very good odds there too. It is one of the highest all rounders in terms of giving good specific and general card quality. Having three known cards on the bottom of your library is less immediately powerful than some scry or reordering at the top but it offers far more ongoing information. Impulse scales brilliantly with smaller libraries in all ways too hence being so extra good in cube. In any sort of control deck I would much prefer a two mana instant card quality spell than a one mana sorcery speed one. Leaving mana open is that much more important and you will have some tap lands you need room to get down. It is not like you can keep one land hands in control decks anyway.
6. Opt
About as low impact as you can get from a card quality card, let alone a spell in general! Opt is very minor but it is also entirely self contained and very painless to play indeed. Essentially it is Preordain with half the scry power in exchange for being instant. Earlier I compared it with the scry lands and that is likely the closest both in effect and power but the role you play the cards in is somewhat different. Opt you cast at your leisure and at the low cost of one mana it should barely ever be detrimental or even noticeable on your curve which is much more so the case with the slightly more potent sorcery alternatives that get in the way of things more. You play a scry land when you can afford a minor tempo hit in exchange for greater consistency. It is almost always occupying the slot of a land. Opt however cycles so has much more the effect of reducing the overall size of your deck. This subtly changes the balances of things in your deck and lets you more accurately hone the land count to exactly what you want. Most control decks want somewhere between 17 and 18 however you cant play half a land. What you can do is play cards like opt so that 17 lands in 39 cards looks a lot more like 17 and bit lands in 40 cards. This can be achieved with any low cost instant cycle card at the small cost of having less initial information. You occasioanlly have to mulligan hands containing Opt or Gitaxian Probe which you might not have had to if you knew what the card you were going to draw was. The pay off with Opt unlike most other cheap instant cycle cards is that you get to scry and therefore usually wind up with more information on average. You will still get the awkward starting hand mulligan choices but overall the Opt will sort you out. Opt lets you balance your deck, like other cheap cycle cards, while also increasing consistency like scry lands do, yet affords you more flexibility and options as to how and when you use it than basically any of the alternatives. I mentioned I play it over Brainstorm often and this is because it is self contained, I don't need to hold it to milk the potential from it, as soon as I have a spare mana at the end of your turn I can fire it off and it will be about as good as it gets. Opt also being such a cheap and painless card to play has a lot of good interactions with prowess style effects and can be employed like a combat trick. As you might have guessed, I really love Opt, I love how it is so minor in effect yet still such a versatile and exciting card.
7. Faithless Looting
Like Vampiric Tutor this red card quality spell costs you a card. Red, being one of the most starved colours for card quality, often sucks this up. Sadly also being one of the weaker card advantage colours as well it cannot use it as much as it would like to. Faithless Looting is a card with many strings to its bow and is used in a wide array of places and roles as a result. First and foremost it scales brilliantly with any graveyard effect cards. The more you have of these or the more your deck is based on such a theme the more powerful Faithless Looting is. Even just a couple of flashback, unearth or recursion cards contained within a red deck wins can push Faithless Looting from a consideration to an auto include. Draw two discard two is a good chunk of immediate action as well as card quality. It is not that far off a Brainstorm and keeps you hitting new things in subsequent draws should you not have that shuffle effect handy. As a one hit one mana card quality spell it is impressively self contained while giving a lot of effect and options. It is the card you most want when you are flooding and usually a card you are wanting should you be suffering a screw. It gives you a much greater scope when building with it. Searing Blaze is one of the best burn spells in magic yet in some formats I am reluctant to run it because it is that little bit more situational than typical burn and can be a dead card. Having a Faithless Looting in my deck makes me that much happier to run the more powerful situational cards like Blaze. Flashback is immense on the card, it means you can dig as deep as an Impulse while drawing four cards. It makes Looting scale well with other discard effects as well as any prowess style triggers you might have. I have had games where I used looting on turn one or two to dig for lands and then flashed it back late game to turn excess lands back into spells. Looting is good enough that you can pretty legitimately play it in any deck but it becomes really quite something when it is in those decks most full of synergies. Easily capable of outperforming Brainstorm. It is the most rounded and the highest offering of general card quality while up there with Impulse on the specific front as well. The price for all this lovely power is costing you a card and this must be forefront in your mind when considering building with it.
8. Vampiric Tutor
Any card for one mana and at instant speed. Vamp is the best one shot card quality spell in magic, the price you pay is losing a card and two life. It is a surprisingly fair card overall. Some decks can afford the price more easily and some decks want the effect more, judging when you have the right amount of both aspects surrounding the card will determine how good it is for you. When you are all about speed you can more easily afford to sac life and cards for the right things. When you are more midrange and have a lot of redundancy then perhaps the vamp is not for you. You can go full circle so to speak and end up with a midrange deck that is so clunky yet so powerful you need a Vamp to even it out and the power of your cards makes up for the card loss. Something like a Necropotence typically refills you in aggressive decks and is a common target for a Vampiric. With a decline in combo and more options for aggro decks Vampiric Tutor has seen a drop in use but remains easier to include than Demonic Tutor. It is as good for specific card quality but is substantially better for general card quality. You don't really want to use it in this capacity but that doesn't mean you aren't going to have to. I have gone on to win more games where I Vamped for a land than those in which I Demonic for one.
9. Demonic Tutor
No life loss or card loss however twice the mana cost and at sorcery speed make Demonic a different sort of uncomfortable to Vampiric. You want card quality to get in the way of your ideal curve as little as possible. Demonic is almost too good! While it is still a bargain for what it does you do not need it to do as much as it does. Preordain will find you that land or bit of action almost as reliably and that is the majority of what you want card quality for. As such it is only when you need specific things for your deck to function, either you are light on answers or are revolving around some sort of engine or synergy that you become happier paying two mana in your turn to get a card you want. A very powerful card that is seeing less and less play with greater tempo and redundancy in the cube. Demonic is also just a single cards worth of quality, something like a Serum Visions or the Top can set you up with more ongoing quality. Cards are so good that adding two mana to the cost of any in an unpowered cube make them pretty awful. Preordain is cheaper and spreads its cost over more cards and therefore is much less painful on the power to mana ratio of the cards in your deck than a Demonic. There are however lots of ways to slightly improve your card quality, there are very few ways to directly get a specific card. For general card quality Demonic is not all that yet it retains a high rating because it can allow for more unusual decks and very specific card quality.
10. Sylvan Library
The original Divining Top, not as versatile as the little artifact but also has some advantages over it. Both are cheap permanents that allow you to effectively reorder the top three cards of your library in an ongoing capacity. Both scale very well with shuffle and scry effects and offer greatly more card quality as a result. Both also afford great synergy with all things top of library based such as miracles, Courser of kruphix, Devler of Secrets, Domri Rade etc. Library is easier to kill, only available in green and slower to come down than Divining Top. It also only triggers once on every one of your turns unlike Top which you can use as much as you have mana for. One use per turn is the most efficient way to obtain a high level of card quality and so the fact that you have to pay no mana to use Library is an advantage overall. Not many cards on this list can be used to generate card advantage, you have to combine Top with a card like Voltaic Key for it to do so or ignore oracle text for Lat-Nam's to situationally do so. A bunch of the cards here are not even card neutral and will cost you a card to play. Sylvan Library however has a built in mechanism whereby you can use it for card advantage as well as card quality or you can let it cost you a card and just use it for quality. It does not have to be around for many turns before it has given you more options than Brainstorm! Four life is a lot to pay for a card but the choice is entirely yours, often life is pretty irrelevant and so it is just free goodies. There are also a bunch of very playable cards that afford big life returns which you can then pour into a Library. Every time you pay 4 life the next time Library activates it will be giving you more information and better card quality than it otherwise would much like having a shuffle effect. Library therefore interacts fairly well with itself. For general card quality, utility and synergy Library is quite significantly better than Demonic Tutor but it is even slower and clunkier to get online. At least green is burstier and able to take those tempo hits far more easily than black.
11. Serum Visions
I class Ponder, Preordain and Serum Visions very much in the same bracket. They all are incredibly similar and while they have their individual strengths and places I will fairly happily play any of these in place of another if I just want a bit of cheap card quality. There are no real abuses that you can do with these cards, they will always cost you a mana in your turn, always replace themselves with a new card and should improve the quality of that card and/or the next few. Typically Serum Visions is regarded as the worst of the three being the only one not banned in modern. Slight of Hand is also in this bracket but is a more noticeable step down in potency. Slight of Hand sees only two cards and gives only two options. Ponder has the most potential for power but can only really achieve this in combination with other cards, much like Brainstorm. Preordain and Serum Visions are a nice balance of being able to afford lots options and information while also remaining self contained and easy to max the power potential. Preordain offers you better quality for the cards you actually get into your hand as well as more immediate action. This makes it better in the late game as well as better at getting you out of screws. Preordain is the most powerful all rounder you can throw into any old deck and have it be good. The reason I have Serum Visions ever so slightly higher is that it is still very very close to Preordain in general all round power, it typically gives more overall information as well (if you keep at least one card from a Preordain scry you see one less card overall than you do with Serum Visions or Ponder), but most of all it is becuase Serum Visions affords you the best synergy with top of library effects. While typically still worse than Top and Brainstorm for miracles, Delver of Secrets and the likes Serum Visions is quite a lot more use than Preordain at setting such things up. This list is heavily influenced by the amount I play cards and how much I see them played, I certainly find I play Serum Visions more than Ponder and Preordain. It is the nicest balance between self contained card quality and top of deck manipulation of the three.
12. Preordain
Lovely little card, see two or three cards, draw one you want now and more likely one you want next turn. It is self contained and is kinder on preventing you clogging up your hand with cards you don't want than a lot of card quality effects. If you just want card quality no fuss then this is likely the card for you. It is the best general card card quality of Serum Visions and Ponder while still offering good specific card quality. Formats like modern seem to be much more interested in specific card quality while I find in cube that general card quality is the most desired. Either way, Preordain is all round made of goodness.
13. Ponder
To my mind this is the least desirable of the good card quality spell for cube play despite thinking it is one of the best ones for a format like modern. To obtain full potential you want shuffle and if you are going to that sort of bother you really want stuff more the power of Top and Brainstorm. Where Ponder excels is in seeing a lot of cards for not a lot of mana, it has better specific card quality than your Preordains and Serum Visions, even your Brainstorms. The thing is, it has far worse specific card quality than the black Tutors, most of the time in cube you just want general card quality, the need for finding specific things is dwindling. If you do want to find specific stuff you go the tutor route, if not then your Ponder has less value than Serum Visions. You get information or quality with Ponder, you do not really get both with any consistency. The fact that you cannot filter any of the cards away should you keep them means you have to have gained some advantage through the reordering to have actually done anything beyond cycling. So often you are looking for land and see one in the next three and are forced to shuffle and take the random. In such a situation you are going to be better off with Preordain or Serum Visions. Ponder is better at setting up miracles than Serum Visions and therefore also Preordain and it ticks the gives a shuffle box which means it will improve other cards you may have like Top and Brainstorm. It is still a great card but one of the ones I find myself playing least.
14. Scroll Rack
Arguably the hardest card in magic to play well. It is a lot more awkward than all the other card quality effects but it does several things that are highly abusable and unique or at least rare. It is expensive as card quality goes but can be used by any colour. It is also the only non-blue way of putting cards from your hand back on top of your library. You can easily see seven new cards with it for just one mana, with enough shuffle you can do that most turns! I have abused it silly with Land Tax for an effective Ancestral Recall on a stick. It is another effect you want to combine with library shuffle else the ongoing value of the quality rapidly declines. On top of this you typically also need strong ways to draw cards, should you start to flag in hand size you can wind up almost locking yourself out of the game with only weaker cards available to you. Scroll Rack is incredibly powerful but it costs you a card and a chunk more tempo than anything else on this list. There are fewer and fewer decks that can accommodate such card but they are lots of fun when you do get them!
15. See Beyond
The poor mans Lat-Nam's Legacy, not because the effect is worse but simply because it is sorcery. On many occasions the effect is better as it gives you more action right away. It is quite a popular card in combo decks as a result. The reason it carries on hanging in the main cube despite being a bit of a cut below the rest is because of the value and rarity of putting cards from hand to library. You only ever play See Beyond if you have a specific need to do this in your deck, perhaps something like a Tinker deck. You still happily play Lat-Nam's and Brainstorm without that need. You never really see See Beyond in control decks, even in miracles it can be left out if you get enough of the afore mentioned better cards. As such it leads a charmed life in the cube but does remain a chunk better and more useful than the weakest card quality out there that has not made this list.
There are a bunch of other worthy cards and groups of things that offer card quality that deserve some mention of why they are not on the list.
Gitaxian Probe
The Sac Lands
These two cards don't provide quite the same card quality as the spells on the list but they still kind of do and are obviously fantastic cards for there own reasons as well. Both cards relatively freely thin your deck by one card, which assuming the rest of the cards are what you want, will increase the power density of your deck. This is a kind of pseudo card quality and a little different to what I was going for, it is hard to rate a sac land in this list because they do so many other things as well.
Creatures offer a lot of card quality in the cube as well. There are good solid threats like Reaper of the Wilds that do so as an incidental perk. There are useful roadblocks like Sea Gate Oracle that represent more of a two for one than card quality. The latter effect is a nice sweetener but it is not the primary reason you play such cards. There are not that many creatures that are sufficiently cheap that you can afford to play them in a similar capacity to something like a Preordain.
Looter il-Kor
Enclave Crpytologist
Are the two best examples of cheap card quality dorks. Both are very good cards but neither really stand up to the level of card quality and reliability you get from the non-creature cards. Looter il-Kor is truely amazing but it has to survive long enough to get in two attacks before it has done half of what Faithless Looting can do. They are slow and vulnerable but they make up for this by also performing other roles, things to hold equipment, use in some sacrificial capacity and so forth. This means I cannot rate them very highly in a list discussing purely card quality.
Slight of Hand
Portent
These are the only two one mana or less cards that are card neutral and have any manipulative effect on your cards that are not cube mainstays. Both are sorcery and both have limitations, the Slight is simply the least digging and the least options of all the cards and really needs to be instant. It does occasionally see play but this is usually when several players are tapping into blue hard. Portent is painfully slow, it has all the limitations of Lat-Nam's and Ponder combined. When you don't need any immediate action Portent is better than Ponder as it can be disruptive but this makes it a bit too unreliable for this sort of card. You want reliability more than anything else.
Wild Guess
Tormenting Voice
The other offerings red has in the card quality department are somewhat lacking, they make See Beyond look positively fantastic. Even with all their shortcomings these similar cards have seen some cube play and would see a whole lot more if it were not for how dangerous they are to use around counter magic.
Lim-Dul's Vault
Diabolic Vision
Are the best gold has to offer on this front. The odd charm has a bit bolted on but it is typically for emergencies only as they are so inefficient. These are both pure card quality spells, somewhat ramped up versions of Vampiric Tutor and Ponder meets Impulse. The Vault is surprisingly good in cube, it is usually comparable life to Vampiric to find a specific thing yet it also has the capacity to tutor for a couple of more vague things, say two lands and any sort of three drop. Instant more than offsets the two mana cost but it is the card disadvantage that means this doesn't see much play. It offers about the most combined specific and general card quality but when you want one kind you play Vampiric or Demonic and when you want the other you just play Ponders and the like. The Visions is pretty awful, being sorcery and costing two is bad. Then on top of this it doesn't allow you to get rid of any dud cards you don't want. Digging five deep is good and is enough cards that reordering starts to be more significant, just not enough!
Truth or Tale
Worldly Council
Telling Time
Words of Wisdom
Anticipate
Make up the list of cards that fall too far short of Impulse. Truth or Tale is deceptive and impressively shit when it comes to playing with it. Worldly Council is fine and can be great but is a little bit narrow for my liking in cube. Anticipate is likely better than Telling Time, the ability to cull away unwanted cards is typically the most valuable aspect of card quality and Anticipate has more of that on offer. Neither compare at all well to Impulse but both are still very playable. Telling Time at least has some good set up potential for miracles etc. and would be the next card I added to the cube if I felt lacking in that area. Anticipate may be slightly better than it but it is sad and offensive to me and doesn't do anything different. I like cards that give choices and variance. You never ever play Anticipate if you could play Impulse instead. There are at least occasions you may elect to Tell Time over an Impulse. Words of Wisdom is a funny one, it is more card advantage than card quality but as it doesn't actually give you card advantage over your opponent (the only measure than has any relevance) I can't quite so easily consider it as that either. What it feels like is a card that gives you quality by giving you more options and action. In some situations it is easily abused and the drawback negated, in others where you face off against brutally redundant decks of burn it is a complete liability.
Muddle the Mixture
Merchant Scroll
Mystic Tutor
Enlightened Tutor
Worldly Tutor
Wild Research
Summoner's Pact
Eladrami's Call
There are of course a whole selection of tutor cards across all the colours, none come close to Vampiric or Demonic. They are all far more niche in what they can get and often clunkier as well. They still offer card quality and are by far and away the most played cards I have mentioned in the article that did not make the list excepting the creatures. They are usually found in the exotic decks and have little to no place in you standard, agro midrange or control.
The Wishes
Like tutors but offering way more utility without any harm to your deck and therefore often well worth that extra mana cost you pay. While wishes can be plenty powerful enough for cube they are tedious to balance properly and make sensible rules for them for the various formats and so I cut them.
Mystic Speculation
A really cute card but far too mana intense and card disadvantagy. It has never seen cube play but I do rather like it!
Strategic Planning
Careful Study
Frantic Search
Planning is somewhat of a See Beyond for decks with some graveyard synergies rather than library ones. Without any synergy to power it up it is too expensive and sorcery, a lot of times in more normal decks the milling of two cards will be painful and you would have much rather been casting Anticipate. With all the delve juice in the Tarkir block Strategic Planning is looking like it currently has its best shot at a run in the A cube. It is at least card neutral unlike its little brother Careful Study which has only ever seen play in decks with a strong graveyard theme. Study is a very good card quality spell but it is far less exciting in blue where you are spoilt for choice than it is in red, flashback aside. Frantic Search is amazing and likely one of the most versatile combo cards in the cube but it is all about the untapping of lands and not the draw discard. Despite costing no mana the need to have three upfront makes it a bit slow as well as losing a card for use as pure card quality.
Sakura Tribe Elder
Nature's Lore
Search for Tomorrow
Sylvan Scrying
Farseek
While all these cards are considered ramp before card quality except the Scrying they do also offer card quality. Typically they fix mana which has given you some quality but they also thin your deck.
Sultai Ascendany
Thassa, God of the Sea
Three mana is really pushing it for card quality prices. Scry 1 per turn is very potent and self contained but notworth three mana. Fortunately Thassa has a lot of other stuff going on and crops up here and there. The Ascendancy is basically scry 2 but to the graveyaard rather than the bottom of library. It offers a lot more card quality than Sylvan Library and also some graveyard synergies but as it does nothing else, is always card disadvantage and is three colours so it has not seen any play yet.
Tibalt
Finally this useless sack of planeswalker is actually a card quality provider. He is just really ineffective at it, you have to do a huge sample size before the averages work out in his favour that he is just far too low impact and risky for any sort of use as card quality. He is unique in that he is a planeswalker cheap enough to be used in this capacity, it is just a shame he is so all round awful.