Up: Interesting take on that challenge. I'm a sucker for token strategies and +1/+1 counter strategies, and this looks great in both as a finisher kind of card. Not quite sure it's worth all that mana though. Solid 8/10
Warp Goyf Creature - Lhurgoyf Ingest (When this creature deals combat damage to a player, that player exiles the top card of their library.) Warp Goyf's power is equal to the number of cards in exile and its toughness is equal to the number of cards in exile plus 1. It flickers through space, feeding on the scraps of forgotten memories. */*+1
Up: While the concept is fine, it seems pretty weak on its own. It can't even fuel itself since its starting power is 0, preventing it from ingesting. I'd give it an alternative way to exile cards, unless it's in an exile-heavy set I suppose.
Aether-Charged Railrider Artifact - Vehicle Crew 3 Trample Whenever ~ deals combat damage to a player, you get that many . Pay : ~ gets +1/+0 until end of turn. 3/3
Down: Make a common Angel, Sphinx, Demon, Dragon, or Hydra.
Up: That looks pretty strong. Something to be afraid of in limited at least. I like it.
Sphinx Fledgling Creature - Sphinx Flying Whenever Sphinx Fledgling deals combat damage to a player, that player names a card, then reveals the top card of their library. If it isn’t the named card, they mill two cards. 2/2
I tried to make a "riddle" in a simple way and with a result that is bearable at common.
Next: Insect tribal
"It's not difficult to make Magic players feel smart." - Mark Rosewater
Furthermore, I consider that Carthage must be destroyed.