Submerged Boneyard

Submerged Boneyard enters tapped.
{T}: Add {U} or {B}.

Spontaneous Mutation

Flash
Enchant creature
Enchanted creature gets -X/-0, where X is the number of cards in your graveyard.

Cemetery Recruitment

Return target creature card from your graveyard to your hand. If it's a Zombie card, draw a card.

Island

Wailing Ghoul

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

Drunau Corpse Trawler

When Drunau Corpse Trawler enters, create a 2/2 black Zombie creature token.
{2}{B}: Target Zombie gains deathtouch until end of turn.

Compelling Deterrence

Return target nonland permanent to its owner's hand. Then that player discards a card if you control a Zombie.

Drag Under

Return target creature to its owner's hand.
Draw a card.

Swamp

Graf Harvest

Zombies you control have menace. (They can't be blocked except by two or more creatures.)
{3}{B}, Exile a creature card from your graveyard: Create a 2/2 black Zombie creature token.

Liliana's Elite

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

Haunted Dead

When Haunted Dead enters, create a 1/1 white Spirit creature token with flying.
{1}{B}, Discard two cards: Return Haunted Dead from your graveyard to the battlefield tapped.

Stitched Mangler

Stitched Mangler enters tapped.
When Stitched Mangler enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.