Urza, Chief Engineer 3
This is very midrange for an artifact synergy card, pretty gold too. The power level however is mental. Three mana 4/5 that makes a construct at the end of each turn with a little menace kicker. That wins real fast. Little else needs doing. Build around only but amazingly actually worth doing!
Sanwell, Avenging Ace 5
This dude is narrow but powerful and with an impressive floor. As such you do not need much support for this to jump into the realms of cube playable. I would be keen to play this in any white aggressive deck with enough support, any aggressive artifact deck with enough white mana, and likely any vehicle based decks. Sanwell works especially well with those being able to more reliably trigger the tap effect immediately. As far as my cube goes I am quite a long way off what I think is enough support. Sanwell is probably starting to get good when you have around five things that can be hit off the trigger and help attack with to protect her. When your deck is stacked with such things, say around a third, then she is pretty nuts.
Scholar of New Horizons 8
This seems outstanding. It is value, utility, options, and all sorts of cool synergies. It can even be ramp and fixing in the right situations! All that for two mana is pretty tasty. Yes, it is pretty slow to be able to get you the land and you may get blown out with some efficient removal and not be able to get those "free" Plains. On a two drop with this much upside I am not losing any sleep over any small shortcomings Scholar might have. I'll consider Arc Trail more than usual when I cast it against red players and that is really all there is too it. Where Scholar goes from good to nuts is when you have something that works particularly well with it, say a saga or a persist dork. Then you able to get all sorts of abusive. Not only will you get free land each turn but also effective free steps on your saga. I expect a return to the ranks for at least History of Benalia, perhaps even Kitchen Finks! Lots of things this is especially good with. This isn't oppressive power but it is a lot of card. It is also interesting and that is big win for white.
Kayla's Music Box 7
White seemingly getting all the love out of this set of commander product. This is a pretty slow card but it is the cheapest ongoing source of near unconditional card advantage. This is three for that first extra card and just one mana each there after. That blows the likes of Mazemind Tome, Endless Atlas, and Reckoner Bankbuster out of the water, each at four then two mana respectively. All of which are either capped or have preconditions. And all of which are the current best in the game for colourless card advantage. It is most commonly white calling on these tools as it is, with white having the least access to card draw. This means that while this is narrower than those purely colourless options it is not nearly as narrow as it might seem. It is not the white in the cost then that sets this apart from those other options so dramatically in cost. It is the speed of return that allows this to be so efficiently costed. It effectively needs two taps per card drawing drawing as soon as able and at least one extra tap than cards gained if being the most turn efficient possible. If you play this on turn two (without ramp) you are not getting anything back from it until turn four. There is also that risk of having this blown up before you get to play cards with it, especially risky if you have some key cards exiled under it. You can also argue that this doesn't put cards in hand and thus doesn't work exactly like card draw but that is rather a semantic thing. If you need more gas in white this is great, likely your best option. If you need to fill your hand up with cards then white has things like Tithe and Land Tax it can use. Overall this seems too efficient not to see some play and be decent. Cards are good and if you can just keep them coming at such a cheap rate then great. I feel like this packs enough punch that I am pretty happy slapping into any heavy white deck I make from aggro through to control.
Thopter Shop 1
Bit expensive to use and all rather capped, narrow, and low tempo to be using just for the value side. I like this but liking something is not enough to make it good.
Blast-Furnace Hellkite 2
Too narrow for general use but easily cheated out with things like Myr Enforcer, prototype cards, perhaps even Oxxida Golem! Threatening if you do and game winning if managed with a pre-existing board presence.
Smelting Vat 1
This looks like a lot of fun. A kind of non-creature artifact Birthing Pod. Fun, but slow, low powered, and really in need of some abuses.
Urza's Workshop 2
Another fun one. This is one of those cards that makes me want to build around it which I always take as a win. Obviously too narrow for most uses but an intriguing deck design question.
Wreck Hunter 2
This is quite a lot of stuff with some scaling but it is not very useful. A 2/2 is whatever and flash isn't helping improve that all that much. This is not really a 2 drop you can curve with either. It is a bit Caller of the Claw and those kinds of cards have proved too situational. This isn't even making dorks, just powerstones, which you then have to take an extra step to have be useful at all. You can power this up yourself by having your own things go in the bin but that is also work to setup and doesn't really help you with the payoff. All in all this card is going to be very hard to fit in anywhere and hard to make it translate into good value in 1v1 play.