msem-instigator

Post a bounty on target creature. (Put a bounty counter on that creature. It has “When it dies, each opponent draws a card” as long as it has a bounty counter on it.)
Draw a card.

When War of Resources enters, recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)
Whenever a creature you control dies, each opponent loses 1 life.

Up to one target creature gets -1/-1 until end of turn.
Recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

Spend only black mana on X.
Up to two target creatures each get -X/-X until end of turn. You gain X life.

Bleed {2}{R} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
Target player loses 2 life. If this spell's bleed cost was paid, it deals 1 damage to each creature that player controls.

Choose any number —
• Each player loses X life.
• Each player discards X cards.
• Each player sacrifices X creatures.
• Each player sacrifices X lands.

Target player discards a card. Until your next turn, whenever that player casts a spell, they discard a card.

Whenever a creature you control enters from a graveyard, target opponent loses life equal to its power.

Destroy target creature.
You gain 2 life.

This spell costs {2} less to cast if it targets a creature or planeswalker card with mana value 3 or less.
Return target creature or planeswalker card from your graveyard to the battlefield.

As an additional cost to cast this spell, sacrifice a creature.
Look at the top three cards of your library. Put two of them into your hand and the other into your graveyard.

Germinate three times. You lose 3 life. (To germinate, put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Each opponent sacrifices a creature. For each creature sacrificed this way, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Target creature gains lifelink or winnow until end of turn. (Damage dealt to it also causes its controller to lose that much life.)
Put the bottom card of your library into your hand.

All creatures get -1/-1 until end of turn.
If ten or more cards are in your graveyard, creatures your opponents control get an additional -1/-1 until end of turn.

Flash
Enchant creature
Enchanted creature gets +2/+2 and has flying and “At the beginning of your upkeep, you lose 1 life and create a 1/1 black Harpy creature token with flying.”

Target creature gets -6/-6 until end of turn.
Create a black enchantment token named Blight with “At the beginning of your upkeep, you lose 1 life.”

Choose one—
• Each opponent sacrifices a creature.
• Each opponent discards two cards.

Enchant creature
Enchanted creature gets +1/+0 for each card type among cards in your graveyard and has menace.
Fleeting {B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards. You gain 2 life.

Search your library for a card, put that card into your hand, then shuffle.
Whenever you cast a spell with mana value 5 or greater, you may cast Words of Eternity from your graveyard without paying its mana cost. If you do, exile it instead of putting it into your graveyard as it resolves.

Destroy target creature or planeswalker, then exile its controller's graveyard.

Legacy (You may play this side of this card only from your graveyard. Exile it if it would be put into a graveyard or not resolve.)
Each opponent sacrifices a creature for each spite counter they have. If they didn't sacrifice any creatures this way, they discard that many cards instead.

When Writhing Gateway enters, you may discard a card. If you do, create a 5/3 black Horror creature token.
{1}{B}{B}, Discard a card: Create a 5/3 black Horror creature token.

Whenever you activate a loyalty ability of Xanigan, the Darkened Cloud, you get an emblem with exalted.
[+2]: Xanigan deals 2 damage to up to one target and you gain 2 life.
[–3]: You draw three cards and you lose 3 life.
[–7]: Xanigan becomes a 7/7 Demon creature with flying and indestructible that's still a planeswalker. Prevent all combat damage that would be dealt to her.