msem-instigator

At the beginning of combat on your turn, look at the top four cards of your library. You may put a creature card with mana value 3 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.

[+2]: Put two +1/+1 counters or loyalty counters on up to one other target creature or planeswalker.
[0]: Cornrose, the Mighty deals 3 damage to target creature. That creature deals damage equal to its power to Cornrose.
[–2]: Until end of turn, target creature gets +X/+X and gains trample, where X is its power.

Harvest (You may tap any number of creatures you control as you cast this spell. If you do, reduce this spell's mana cost by their total power.)
Search your library for a creature card with mana value X or less and put it onto the battlefield. Then shuffle.

Whenever another enchantment you control enters, you may put a progress counter on Corporate War.
[progress 2-5] {W}{B}, Sacrifice a creature or enchantment: Destroy target creature or enchantment.
[progress 6+] Sacrifice a creature or enchantment: Destroy target permanent.
Sacrifice a creature or enchantment: Destroy target permanent.

Whenever another Zombie you control enters, you may pay {1}{B}. If you do, exile target creature card from a graveyard. You gain life equal to its toughness.

{T}, Remove a +1/+1 counter from a creature you control: You draw a card and you lose 1 life.

Corpse Thief can't be blocked by creatures with greater power.
Whenever Corpse Thief deals combat damage to a player, return target creature card from your graveyard to your hand.
{3}{G}{G}: Mill half your library, rounded down. Transform Corpse Thief. Activate only as a sorcery.

Defender
Whenever a land you control enters, you may exile target permanent card from your graveyard.
Sacrifice a land: Put a card exiled with Corpsebark into its owner's hand.

When Zwurg enters, you may discard your hand. If you do, draw X cards and add X {R}, where X is the number of different sources that dealt damage to an opponent this turn.

Whenever another Zombie or Demon creature you control enters, 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.”)

Menace
Whenever you cast an instant or sorcery spell, create a 2/2 black Zombie creature token. This ability triggers only once each turn.

When target creature you control dies this turn, return it or another creature card with an equal or lesser mana value from your graveyard to the battlefield tapped.

Haste
This creature can't block.
{2}{R}: Return this card from your graveyard to your hand.

Return target creature or planeswalker card from your graveyard to the battlefield. If that card was a creature, it's an Actor in addition to its other types.

Menace
Sacrifice another creature: Corpulent Gibberer deals 1 damage to any target.
Evoke {1}{R} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Exile a creature card from your graveyard: Put two loyalty counters on Corpus. Activate only as a sorcery and only once each turn.
[–2]: You may sacrifice a creature. If you do, create a 4/4 red Horror creature token with menace. Otherwise, create a 2/2 black Zombie creature token.
[–4]: Search your library for two non-Corpus cards and reveal them. Put one into your hand and the other into your graveyard, then shuffle.

First strike, trample
{2}{R}, Sacrifice a land: Corrignos' Rage gets +3/+0 until end of turn.

At the beginning of your upkeep, choose one —
• You lose 1 life.
• You draw two cards and you lose 3 life.
• Search your library for a card, put it into your hand, then shuffle. You lose 5 life.

When Corrupt Warden enters, up to one target creature gets -X/-X until end of turn, where X is the number of card types among cards in your graveyard.

This spell costs {1} less to cast for each card type among cards in your graveyard.
Deathtouch

Flying
{1}{B}, {T}: Destroy target creature that was dealt damage this turn.

Rhapsody {5}{R}{R} (Pay {5}{R}{R} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
When Corrupted Guardian enters, it deals damage equal to its power to up to one target player or planeswalker.

(Transform this if it's not attached to a creature. Pay {3}{B} as a sorcery to unattach it.)
Enchant creature you control
Corrupted Mount's rider gets +5/+4 and can't block.

Whenever an opponent casts a spell, that player gets a poison counter unless they pay {1}.
As long as an opponent has five or more poison counters, Corrupted Soothsayer gets +2/+1 and has flying.

Invocation — When you spend four or more mana to cast a spell or activate an ability during your turn, transform Corrupted Sorcerer.