Drivnod, Carnage Dominus

If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
{B/P}{B/P}, Exile three creature cards from your graveyard: Put an indestructible counter on Drivnod, Carnage Dominus. ({B/P} can be paid with either {B} or 2 life.)

Cemetery Reaper

Other Zombie creatures you control get +1/+1.
{2}{B}, {T}: Exile target creature card from a graveyard. Create a 2/2 black Zombie creature token.

Rooftop Storm

You may pay {0} rather than pay the mana cost for Zombie creature spells you cast.

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.)

Fleshbag Marauder

When Fleshbag Marauder enters, each player sacrifices a creature of their choice.

Diregraf Colossus

Diregraf Colossus 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.

Headless Rider

Whenever Headless Rider or another nontoken Zombie you control dies, create a 2/2 black Zombie creature token.

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

Lord of the Accursed

Other Zombies you control get +1/+1.
{1}{B}, {T}: All Zombies gain menace until end of turn.

Zombie Apocalypse

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

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Champion of the Perished

Whenever another Zombie you control enters, put a +1/+1 counter on Champion of the Perished.

Diregraf Captain

Deathtouch
Other Zombie creatures you control get +1/+1.
Whenever another Zombie you control dies, target opponent loses 1 life.

Have

Wilhelt, the Rotcleaver

Whenever another Zombie you control dies, if it didn't have decayed, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)
At the beginning of your end step, you may sacrifice a Zombie. If you do, draw a card.