I don't know much about Spider-Man (or legally distinct Arachnid Chap), but I like to think I know something about limited Magic. This is going to be a weird format - the first of its kind - but a lot of the usual rules of thumb still apply, regardless of whether you're playing pick-two at your LGS or Premier Draft on Arena. You're still playing Limited, after all.

One quick disclaimer: you should know that I'm writing this after the early access event but before the full release on Arena. I have a little bit of anecdotal evidence to go on, but that's it. I'm pretty confident the cards here are good, but if they don't end up being the absolute best cards in the format, that won't be a huge surprise.

White

Flying Man is rarely a good card in any format, but there's a lot more going on with this card than your typical 1/1 flier. Web-slinging wants you to have creatures with enters or leaves the battlefield abilities. Check. It also prefers those creatures to be cheap and easily replayed. Check. City Pigeon is going to be a great role player in White decks without ever looking particularly impressive.

Speaking of web-slinging, this is a great pay-off, and I'm not just saying that because he's canonically my compatriot. It's a card draw engine that helps to set itself up by slinging another creature back to your hand so that you can re-cast it and trigger Spider-UK on the same turn. If this doesn't die quickly, it will take over any game.

Blue

A 4/5 hexproof for five is pretty good, and it looks fairly trivial to reach that in the format. An 8/8 hexproof isn't that hard to reach, either, and at that point your opponent will be very unhappy to see the doctor.

It makes sense that the doctor's invention works well with him, doesn't it? This becomes a 3/3 flier pretty quickly, and anything beyond that starts to get out of hand (or tentacle). You don't have to do much work to make this card good, but it pays you off in a huge way.

Black

Boring answer, but with a bit of nuance. I'm not totally sure which common Black removal spell is better, between this and Venom's Hunger. If you're fighting for every life point against an aggressive deck, Hunger might be better - assuming you can easily reduce the cost. But then again, Sting always costs two and also works as a combat trick. Sting is more flexible, albeit with a slightly narrower range, so I'm giving it the edge.

More villains! This is a narrower version of Honest Rutstein, but that card was incredible. Tombstone is still excellent. A lot of good creatures are villains anyway, especially if you're Dimir, so you're rarely going to feel the pinch. This benefits from being in the pick-two format, since you can nab another villain when you add this to your pile.

Red

Honestly, Red commons don't seem all that exciting to me, but at least this one has a high upside. The mana sink ability might be good in the late game if you're flooding out and the triggered ability is a fine bonus for casting your expensive spells.

Now this is a mayhem pay-off! Casting this on turn two and getting in for a few points a turn is nice. Comboing off with numerous mayhem creatures is even better. People are going to take a lot of damage from this and Raging Goblinoids.

Green

I'm putting this here on the proviso that you are easily able to sling it. At face value, this card is not that great, but at three mana it's well above rate. It also helps your other web-slinging cards by being a creature you're happy to bounce and play again, although at that point you likely are paying five for the privilege.

If spider tribal is a thing in this set - and it really should be - Wall Crawl is a nice reward. Gaining a food's worth of life is nice, but making a 3/2 and anthem-ing most (hopefully) of your board is what makes this card shine. Amusingly, there are no defenders in the entire set unless you're playing simic and making Hide in Mundanity a little bit better.