Undead Butler

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

Rot-Tide Gargantua

Exploit (When this creature enters, you may sacrifice a creature.)
When Rot-Tide Gargantua exploits a creature, each opponent sacrifices a creature of their choice.

Rise from the Tides

Create a tapped 2/2 black Zombie creature token for each instant and sorcery card in your graveyard.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Swamp

Repository Skaab

Exploit (When this creature enters, you may sacrifice a creature.)
When Repository Skaab exploits a creature, return target instant or sorcery card from your graveyard to your hand.

Island

Butcher Ghoul

Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Selhoff Entomber

{T}, Discard a creature card: Draw a card.

Headless Rider

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

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Fell Stinger

Deathtouch
Exploit (When this creature enters, you may sacrifice a creature.)
When Fell Stinger exploits a creature, target player draws two cards and loses 2 life.

Hero's Downfall

Skull Skaab

Exploit (When this creature enters, you may sacrifice a creature.)
Whenever a creature you control exploits a nontoken creature, create a 2/2 black Zombie creature token.

Chill of the Grave

This spell costs {1} less to cast if you control a Zombie.
Tap target creature. It doesn't untap during its controller's next untap step.
Draw a card.

Gisa and Geralf

When Gisa and Geralf enters, mill four cards.
Once during each of your turns, you may cast a Zombie creature spell from your graveyard.

Thirst for Discovery

Draw three cards. Then discard two cards unless you discard a basic land card.

Shipwreck Marsh

Shipwreck Marsh enters tapped unless you control two or more other lands.
{T}: Add {U} or {B}.

Archghoul of Thraben

Whenever Archghoul of Thraben or another Zombie you control dies, look at the top card of your library. If it's a Zombie card, you may reveal it and put it into your hand. If you don't put the card into your hand, you may put it into your graveyard.

Stitched Assistant

Exploit (When this creature enters, you may sacrifice a creature.)
When Stitched Assistant exploits a creature, scry 1, then draw a card. (To scry 1, look at the top card of your library, then you may put that card on the bottom.)

Undying Malice

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."