I got as far as Purify (exactly the effect you suggested) and Deflagration (destroys an improvement), after which I discarded the whole idea as "too complex".
I'm not done reading all the stuff in the WoE section, so I'm not quite into it, yet. But to throw a couple of ideas around that might inspire someone:
All spells are discarded after use, except gravity which discard another card.
Paralell Universe Quintessence -> Invisible for x turns.
Unstable Gas -> In the next NPC fight, that NPC has 20 less maxhealth (does not stack, opponent just surrenders when hp are below 20)
Steal -> Steal a card from target.
Poison. -> One is sick for x turns. (can't take any actions)
Graboid -> Spawns a NPC that attacks opponents entering that field. (there until defeated)
Chaos Seed -> Does NOT cause cure
Rage Poiton -> Free Attack. Or a follow attack costs less action points.
Cat-A-Pult. -> throws around schrödinger cats.
Adrenaline -> 1 additional movement.
Miracle -> Used before battle. If you lose, you get a rematch and the previous isn't counted. (probably something else is better than a rare card)
Either Precognition -> Get information on something you usually don't get. Or: Golden Hourglass -> One additional action point. (discard 2 time Pillars when used)
Purify -> Cures negative effects.
Dagger -> Target opponent starts with 10 less health (surrenders when hp goes below 10)