Have

Zombie Apocalypse

Return all Zombie creature cards from your graveyard to the battlefield tapped, then destroy all Humans.

Swamp

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Go for the Throat

Mire Triton

Deathtouch
When this creature enters, mill two cards and you gain 2 life. (To mill a card, put the top card of your library into your graveyard.)

Getting

Undead Butler

When this creature enters, mill three cards. (Put the top three cards of your library into your graveyard.)
When this creature dies, you may exile it. When you do, return target creature card from your graveyard to your hand.

Champion of the Perished

Whenever another Zombie you control enters, put a +1/+1 counter on this creature.

Diregraf Colossus

This creature enters with a +1/+1 counter on it for each Zombie card in your graveyard.
Whenever you cast a Zombie spell, create a tapped 2/2 black Zombie creature token.

Stitcher's Supplier

When this creature enters or dies, mill three cards. (Put the top three cards of your library into your graveyard.)

Bone Shards

As an additional cost to cast this spell, sacrifice a creature or discard a card.
Destroy target creature or planeswalker.

Tainted Remedy

If an opponent would gain life, that player loses that much life instead.

Unbreathing Horde

This creature enters with a +1/+1 counter on it for each other Zombie you control and each Zombie card in your graveyard.
If this creature would be dealt damage, prevent that damage and remove a +1/+1 counter from it.

Gravecrawler

This creature can't block.
You may cast this card from your graveyard as long as you control a Zombie.

Death Baron

Skeletons you control and other Zombies you control get +1/+1 and have deathtouch. (Any amount of damage they deal to a creature is enough to destroy it.)

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.

Mortuary Mire

This land enters tapped.
When this land enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Deathmark

Terror Tide

Fathomless descent — All creatures get -X/-X until end of turn, where X is the number of permanent cards in your graveyard.

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Swift End

Destroy target creature or planeswalker. You lose 2 life. (Then exile this card. You may cast the creature later from exile.)