msem-instigator

Whenever a creature enters, return each other creature controlled by the same player to its owner's hand.

Nonland permanents have “This permanent doesn't untap during your untap step” and “{2}: Untap this permanent.”

All creatures get -4/-4 until end of turn. If a creature would die this turn, exile it instead.

When Abberant Frostbringer enters, tap up to one target creature. If you do, put two stun counters on that creature. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Skip your draw step.
Your maximum hand size is equal to Abhorrent Academic's power.
At the beginning of your upkeep, if you have fewer cards in your hand than your maximum hand size, draw cards equal to the difference.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Abhorrent Exhumer enters, if it engorged a creature card, you may return target creature card from your graveyard to your hand.

Put a +1/+1 counter on target creature. Prevent all combat damage other creatures would deal this turn.

Legendary spells you cast have nonlegendary cascade. (When you cast that spell, exile cards from the top of your library until you exile a nonlegendary nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)

At the beginning of your end step, you may pay {W}. If you do, exile target creature you control, then return that card to the battlefield under your control.

Haste
Whenever Abominable Auteur attacks, you may return target creature card with mana value 3 or less from your graveyard to the battlefield. If that card's mana value was 1 or less, it enters tapped and attacking.

Destroy target creature with power 4 or greater. You gain 2 life.

Menace
Whenever Abomination Blackguard deals combat damage to an opponent, you may draw a card. If you do, you lose 1 life.

When Abomination Broodmother dies, create a 3/2 green Horror creature token.

When Abomination Emissary enters, target player mills six cards.

Abomination Sculptor has deathtouch and lifelink as long as it's attacking.

Destroy target creature or planeswalker.
Crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Return target creature card from your graveyard to the battlefield.
Fuse (You may cast one or both halves of this card from your hand.)

Glitch {1} (Remove one [restriction] for each time you pay the glitch cost.)
Create a token that's a copy of target [noncreature] permanent [you control].

Destroy target artifact or land.

[+1]: Create a 1/1 black Faerie creature token with flying and a 2/2 white Spirit Noble creature token with lifelink.
[–X]: Target creature gets -X/-X until end of turn. Its controller loses X life.
[–7]: You get an emblem with “Whenever a permanent you control enters, you may have it gain flying and vigilance and become a 4/4 Angel creature in addition to its other types.” (This effect lasts indefinitely.)

Bleed {1}{U/R} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
Copy target instant or sorcery spell. You may choose new targets for the copy.

Protection from noncreatures and from creatures with power 3 or less
Players dealt damage by Absurdity also get that many poison counters. (A player with ten or more poison counters loses the game.)
When Absurdity is put into a graveyard from anywhere, shuffle it into its owner's library.

Search your library for a basic land card and put it onto the battlefield tapped, then shuffle. You gain 1 life for each land you control.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Cycling {G} ({G}, Discard this card: Draw a card.)

Deathtouch
Abyss Surger enters with X +1/+1 counters on it, where X is the greatest power among creature cards in your graveyard.