msem-instigator

Zygos, Underworld Scourge's power and toughness are each equal to the number of cards you own in exile and in your graveyard.
Spells you cast have “As an additional cost to cast this spell, you may exile any number of cards from your graveyard. This spell costs {1} less to cast for each card exiled this way.”

Gain control of target artifact, creature, or planeswalker if its mana value is 4 or less or if you cast A Sucker for You from a graveyard.
Reconstruct {9}{U}{U}{U} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

For each basic land type, search your library for a card of that type, then put it onto the battlefield tapped, then shuffle.

When AOSE Lab Tech enters, draw three cards, then discard two cards unless you discard an artifact card.

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
Abandon Life and Hope deals 5 damage to target creature or planeswalker.

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.)

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

When Abomination Emissary enters, target player mills six cards.

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

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.)

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.

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Abyssal Accuser must be blocked if able.

Haste
Disgraced 1 (This enters with a -1/-1 counter. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)

Whenever Abyssal Stalker attacks, defending player discards a card at random.
When Abyssal Stalker dies, you may choose a creature. If you do, exile Abyssal Stalker. When the chosen creature leaves the battlefield, return Abyssal Stalker from exile to the battlefield tapped.

Exile target creature or planeswalker and up to one target card from its controller's graveyard.

If a nontoken creature you don't control would die, exile it instead.
Once each turn, you may cast a card exiled with Accursed Existence.

Flying
{2}{W}, Exile a non-Spirit creature card from your graveyard: Create a 1/1 white Spirit creature token with flying.

Menace (This creature can't be blocked except by two or more creatures.)
When Achet-Aton, Living God enters, if your life total is less than 5, your life total becomes 5.
As long as you have 5 or more life, damage that would reduce your life total to less than 5 reduces it to 5 instead.

Flying, lifelink, deathtouch

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
As you choose targets for an instant or sorcery spell, choose up to one additional target.
At the beginning of combat on your turn, gain control of another target creature until end of turn. Untap that creature. It gains haste until end of turn.

When Adamant Healer enters, you may move any number of counters from target creature onto another target creature with the same controller.

Haste
Whenever two or more creatures you control deal combat damage to a player, tap those creatures, then gain control of target creature you don't control until end of turn. Untap that creature. It gains haste until end of turn. After this phase, there's an additional combat phase.

As long as it's your turn, Otto is an Otter Soldier creature with indestructible and “This creature's power and toughness are each equal to twice the number of creatures you control.”
[+1]: Create a 2/2 green and white Otter Soldier creature token.
[–8]: Draw cards equal to the greatest power among creatures you control, then you gain life equal to the greatest toughness among creatures you control.

Civilized — Adorned Naga gets +2/+0 and has menace as long as you control an artifact, a creature, and an enchantment.