Lord of the Accursed

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

Island

Bladestitched Skaab

Drowned Catacomb

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Death-Priest of Myrkul

Skeletons, Vampires, and Zombies you control get +1/+1.
At the beginning of your end step, if a creature died this turn, you may pay {1}. If you do, create a 1/1 black Skeleton creature token.

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Diregraf Captain

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

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.)

Geralf, Visionary Stitcher

Zombies you control have flying.
{U}, {T}, Sacrifice another nontoken creature: Create an X/X blue Zombie creature token, where X is the sacrificed creature's toughness.

Liliana's Mastery

Zombies you control get +1/+1.
When Liliana's Mastery enters, create two 2/2 black Zombie creature tokens.

Snow-Covered Swamp

Headless Rider

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

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

Undead Augur

Whenever Undead Augur or another Zombie you control dies, you draw a card and you lose 1 life.

Liliana's Devotee

Zombies you control get +1/+0.
At the beginning of your end step, if a creature died this turn, you may pay {1}{B}. If you do, create a 2/2 black Zombie creature token.

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.