Dimir is another fairly weak guild in terms of the gold cards it offers the cube. Not only are the cards fairly weak on average but there are also very few that have seen play in cube compared to the other guilds. Many of those that have seen play are specific combo pieces or parts for highly narrow decks such as mill. Some of the golden oldies have not faired so well in the changing magic meta like Mr Teeth here on my left who would have been in most top 10 dorks lists when first released.
10. Lim-Dul's Vault
9. Far / Away
8. Tezzeret, Agent of Bolas
7. Oona, Queen of Fea
5. Sygg, River Cutthroat
4. Shadowmage Infiltrator
2. Dimir Charm
1. Baleful Strix
Lim-Dul's Vault is not a well known or common cube card however it is one of the best tutor effects in the format. Demonic and Vampiric are better but the Vault does have advantages over them and is not that far behind in power. You shouldn't ever have to pay more than five life to see every card in your deck and the average life payment is going to be as close to that for Vampiric Tutor as makes little odds. The big upside on the Vault is that you get to have a free Index after you have found the card you are after. If it is just a land you needed you can chose one that has the most suitable other cards to accompany it over the subsequent four turns. In the combo era this was a mainstay but sees basically no play any more with tutor effects being far less in demand, particularly those that incur card disadvantage.
Tezzeret, Agent of Bolas is a card I have never had be good for me yet have on good authority that it is one of the better planeswalkers. I have always found the five mana Tezz to be vastly more effective, you are typically playing artifact ramp with either and so the coloured mana is harder to get than the colourless portion making the five mana Tezz easier to play. He also scales better with your artifacts for both the untap and the tutor. Four mana Tezz needs a much higher artifact count to work well and is far slower to impact the game. I appreciate the power of Tezzeret, Agent of Bolas however he fits only in a narrow selection of deck types and is doubly awkward to include in them based on being gold.
Oona, Queen of Fea is a fine card that should break any stalled game rapidly and win most games if unanswered. This is what you should expect from a six mana dork however Oona is better than most at winning games when you have spare mana. Obviously compared to the six drops that do things without mana investment such as Consecrated Sphinx or the Titan cycle she lacks some tempo. The reason she is so good at winning games is that she provides three separate forms of attack, firstly she is a 5/5 flier herself which is quite a serious thing to keep at bay. Secondly she generates an army of flying tokens that will be able to swarm past any would be blockers capable of holding of Oona herself and lastly she will mill their library to nothing in fairly short order allowing her and all her minions to hold back and defend if needed while still working towards a win. Hybrid mana works in her favour as it does with most cards that have a healthy portion of colourless requirement in their cost. In many ways she is like Moloku the Clouded Mirror, Oona makes tokens less effectively but doesn't set you back in subsequent turns in doing so.
Psychatog is a card that has never performed as well in cube as it has in other formats. Part of this is only having a single copy of it and everything else making you unable to rely on the Tog to do what you want. You can't lay one early and hold the ground as you risk losing it and thus losing a main win condition. You can't freely exile any card you like from your yard either as you have to pay attention to your recursion and reshuffle effects for cards you may well need again. Also, with only 40 card decks you are having to exile the majority of it most of the time you are making the Tog lethal. Tog has been used in madness and reanimate strategies however being a reasonably poor early tempo play and costing three mana just as a discard outlet make him weak in both these decks. Despite all this Tog saw a lot of play in the early days of the cube as there simply were not many creatures that were anywhere near as good. Now however any deck that might have wanted the Tog is just going to play something like Vampire Nighthawk instead. The card is too abusable and versatile to ever fully stop seeing play but it is long past the hay day of Mr Teeth.
Shadowmage Infiltrator, like Psychatog is not the card he once was. He is slow and vulnerable, generally incurs a tempo loss and is also fairly easy to block. Jace Beleren and Phyrexian Arena both see much more play as they are more reliable ways to gain a steady flow of extra cards. Rather than occupying a card draw slot in my deck I now allocate Infiltrator to the chump blockers list as a 1/3 is still a fine size to block with and it means I haven't built my deck wrong when the Infiltrator dies without drawing any cards for me. While still a very playable card it now does a fairly different role.
Recoil is a great card and the first on this list which really deserves a cube slot. Often called the instant Vindicate you can't go too far wrong with Recoil. It is a great out, it is outstanding late game removal, it offers tempo and card parity and is impressively versatile. The fact that it hits lands is what assures it a cube space as bounce lands and man lands are incredibly good targets for bounce and abundant in my cube. If you are also packing any discard your Recoil will simply become a Vindicate around the midgame which is doubly yummy in blue and black where ways of dealing with artifacts and enchantments are limited and awkward.
Dimir Charm has been impressive thus far in cube, it has found itself in more different decks and seen more play than any of the other new charms even if it has not been quite so blow out powerful as Selesnya, Rakdos or Boros Charms. It is most like to Izzet Charm in that it has three different yet desirable control effects however you always feel like you get far more value out of Dimir Charm than Izzet. Dimir Charm has also wound up in several agro and combo decks despite seeming to be mostly a control card. It is especially satisfying to counter a Bonfire of the Damned or Terminus that has been carefully set up to be cast in your attack step. I am also partial to getting a pseudo Time Walk out of it when my opponent has nothing going on and I give them a dud draw. Also quirky as a way to put reanimator targets in the bin. It is cheap and versatile which is what good instants are made of.
Here is the rather short list of other Dimir cards that have had play in the cube, mostly they are mill cards or niche combo peices and are therefore about as narrow as it gets.
Glimpse the Unthinkable
Shadow of Doubt