Earl of Squirrel.

I would basically be in favor of taking any card with a mechanic named “squirrellink.” In reality, squirrellink is a very strong ability. If you trade off Earl for a 4/4, you’ll be left with four 1/1 tokens! If you’re able to do damage with Earl and it sticks around, then you’ll be left with four 2/2 tokens. If you have any other creature tokens, they’ll become Squirrels and you’ll get the incidental pump effect bonus of Earl of Squirrels.

Honorable Mention: Magic Word.

This is a really strong card. It’s basically an all-purpose removal spell. You do have to be careful—you don’t want to choose a word that will accidentally cause bad things to happen. For instance, I wouldn’t choose “done,” “pass,” or “go.”

Rules Lawyer.

This card is a complete bomb. You can’t lose if it’s in play. Your creatures can’t die to damage or having 0 toughness, and this includes the Rules Lawyer itself. I don’t know all the cards inside and out, but I’m guessing there are very, very few ways in the entire format to remove Rules Lawyer from the battlefield.

Honorable Mention: Cogmentor.

This seems like one of the better cards to start a Draft with if you’re interested in drafting a Contraption deck, and why wouldn’t you be? The downside to the Contraptions is that you only get to crank your best one every few turns. Not with Cogmentor. With Cogmentor you can just keep reassembling your best Contraption and moving it to a new sprocket, so that you’re able to crank it turn after turn. Seems very strong. After drafting this you should do your best to get a very powerful Contraption or two.

Urza, Academy Headmaster.

Basically, if you follow the rule of “always first-pick the planeswalker” in Limited, you’ll do pretty well. Granted, you don’t actually know what this one does, and it costs WUBRG to cast, but oh well, I’m taking it. I can only imagine the various abilities are pretty powerful. (Spoiler alert: I went to the website and did a bunch of abilities at random. It looks like the +1 will generate one random planeswalker plus ability, -1 will generate one random minus planeswalker ability, but not ultimates, and the -6 will give you one random ultimate. Pretty powerful, and definitely fun.)

Honorable Mention: Super-Duper Death Ray.

A direct damage spell with trample is pretty cool. This will basically allow you to remove your opponent’s best creature, provided it has 4 or less toughness, and then you’ll deal a damage or two to your opponent. For a 3-mana instant, you really can’t complain. The most fun part of this card will probably be casting it: “I’ll play Super-Duper Death Ray targeting your Squirrel.”

Pet Project.

This looks like one of the more powerful contraptions. Every three turns you’ll be able to put a creature card from your opponent’s graveyard onto the battlefield under your control. This will give you some time to trade off the creature so that you have more fodder, or potentially find a removal spell, a mill card, or any other way to get creatures into your opponent’s graveyard so that you can keep cranking the Pet Project.

Honorable Mention: Animate Library.

This is basically a 6-mana creature that should be big enough to win the game outright every time it connects. In Limited, games don’t usually go that long, so on turn 6, you’ll have something like a 25/25 creature. 6 mana for a creature that big is a real bargain.

Incite Insight.

This card looks like a bomb rare to me. Just make sure to get at least 3 Contraptions after you take it, then when you cast it, you can assemble a Contraption on each sprocket to get max value. (As I wrote that, I found it hard to believe that what I was writing was actually about a Magic card, even in an UN- set.)

Honorable Mention: Bee-Bee Gun.

Much better than a real bee-bee gun, since you have no chance of shooting your eyes out. This is a strong card. The ability is powerful if you can find a massive creature on your side of the table, or you’re facing down a swarm of Squirrels or weenie creatures in general. Even just being able to use it to pick off one creature is very strong, and you’d be happy to have one.