Have

Ghoul's Feast

Target creature gets +X/+0 until end of turn, where X is the number of creature cards in your graveyard.

Corpse Churn

Mill three cards, then you may return a creature card from your graveyard to your hand. (To mill three cards, put the top three cards of your library into your graveyard.)

Shadowborn Demon

Flying
When Shadowborn Demon enters, destroy target non-Demon creature.
At the beginning of your upkeep, if there are fewer than six creature cards in your graveyard, sacrifice a creature.

Stitcher's Supplier

When Stitcher's Supplier enters or dies, mill three cards. (Put the top three cards of your library into your graveyard.)

Oversold Cemetery

At the beginning of your upkeep, if you have four or more creature cards in your graveyard, you may return target creature card from your graveyard to your hand.

Thriving Moor

Thriving Moor enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Graveblade Marauder

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever Graveblade Marauder deals combat damage to a player, that player loses life equal to the number of creature cards in your graveyard.

Ossuary Rats

When Ossuary Rats enters, it deals X damage to target creature or planeswalker an opponent controls, where X is the number of creature cards in your graveyard.

Suspicious Shambler

{4}{B}{B}, Exile this card from your graveyard: Create two 2/2 black Zombie creature tokens. Activate only as a sorcery.

Revenant

Flying
Revenant's power and toughness are each equal to the number of creature cards in your graveyard.

Gorging Vulture

Flying
When Gorging Vulture enters, mill four cards. You gain 1 life for each creature card milled this way. (To mill four cards, put the top four cards of your library into your graveyard.)

Spark Reaper

{3}, Sacrifice a creature or planeswalker: You gain 1 life and draw a card.

Boneyard

Liliana's Elite

Liliana's Elite gets +1/+1 for each creature card in your graveyard.

Pit Keeper

When Pit Keeper enters, if you have four or more creature cards in your graveyard, you may return target creature card from your graveyard to your hand.

Necrotic Wound

Undergrowth — Target creature gets -X/-X until end of turn, where X is the number of creature cards in your graveyard. If that creature would die this turn, exile it instead.

Wailing Ghoul

When Wailing Ghoul enters, mill two cards. (Put the top two cards of your library into your graveyard.)

Moodmark Painter

Undergrowth — When Moodmark Painter enters, target creature gains menace and gets +X/+0 until end of turn, where X is the number of creature cards in your graveyard. (It can't be blocked except by two or more creatures.)