Mass of Ghouls

Flesh-Eater Imp

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Sacrifice a creature: Flesh-Eater Imp gets +1/+1 until end of turn.

Village Cannibals

Whenever another Human creature dies, put a +1/+1 counter on Village Cannibals.

Spike Cannibal

Spike Cannibal enters with a +1/+1 counter on it.
When Spike Cannibal enters, move all +1/+1 counters from all creatures onto it.

Cannibalize

Choose two target creatures controlled by the same player. Exile one of those creatures and put two +1/+1 counters on the other.

Oath of Ghouls

At the beginning of each player's upkeep, that player chooses target player whose graveyard has fewer creature cards in it than their graveyard does and is their opponent. The first player may return a creature card from their graveyard to their hand.

Ghoulsteed

{2}{B}, Discard two cards: Return Ghoulsteed from your graveyard to the battlefield tapped.

Zombie Cannibal

Whenever Zombie Cannibal deals combat damage to a player, you may exile target card from that player's graveyard.

Ghouls' Night Out

For each player, choose a creature card in that player's graveyard. Put those cards onto the battlefield under your control. They're black Zombies in addition to their other colors and types and they gain decayed. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)