Rise of the Dread Marn

Create X 2/2 black Zombie Berserker creature tokens, where X is the number of nontoken creatures that died this turn.
Foretell {B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Deathreap Ritual

Morbid — At the beginning of each end step, if a creature died this turn, you may draw a card.

Slaughter Specialist

When Slaughter Specialist enters, each opponent creates a 1/1 white Human creature token.
Whenever a creature an opponent controls dies, put a +1/+1 counter on Slaughter Specialist.

Clackbridge Troll

Trample, haste
When Clackbridge Troll enters, target opponent creates three 0/1 white Goat creature tokens.
At the beginning of combat on your turn, any opponent may sacrifice a creature. If a player does, tap Clackbridge Troll, you gain 3 life, and you draw a card.

Suffer the Past

Exile X target cards from target player's graveyard. For each card exiled this way, that player loses 1 life and you gain 1 life.

Mutilate

All creatures get -1/-1 until end of turn for each Swamp you control.

Massacre Girl

Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.

Flesh Allergy

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature. Its controller loses life equal to the number of creatures that died this turn.

Liliana's Standard Bearer

Flash
When Liliana's Standard Bearer enters, draw X cards, where X is the number of creatures that died under your control this turn.

Cry of the Carnarium

All creatures get -2/-2 until end of turn. Exile all creature cards in all graveyards that were put there from the battlefield this turn. If a creature would die this turn, exile it instead.

Grismold, the Dreadsower

Trample
At the beginning of your end step, each player creates a 1/1 green Plant creature token.
Whenever a creature token dies, put a +1/+1 counter on Grismold, the Dreadsower.

Bloodcrazed Paladin

Flash
Bloodcrazed Paladin enters with a +1/+1 counter on it for each creature that died this turn.