Sedraxis Alchemist

When Sedraxis Alchemist enters, if you control a blue permanent, return target nonland permanent to its owner's hand.

Dreadhorde Arcanist

Trample
Whenever Dreadhorde Arcanist attacks, you may cast target instant or sorcery card with mana value less than or equal to Dreadhorde Arcanist's power from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Phyrexian Crusader

First strike, protection from red and from white
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Black Cat

When Black Cat dies, target opponent discards a card at random.

Boris Devilboon

{2}{B}{R}, {T}: Create a 1/1 black and red Demon creature token named Minor Demon.

Eternal Taskmaster

Eternal Taskmaster enters tapped.
Whenever Eternal Taskmaster attacks, you may pay {2}{B}. If you do, return target creature card from your graveyard to your hand.

Spineless Thug

Escaped Null

Lifelink
Whenever Escaped Null blocks or becomes blocked, it gets +5/+0 until end of turn.

Marauding Knight

Protection from white
Marauding Knight gets +1/+1 for each Plains your opponents control.

Vile Entomber

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When this creature enters, search your library for a card, put that card into your graveyard, then shuffle.

Dreadwing

{1}{U}{R}: Dreadwing gets +3/+0 and gains flying until end of turn.

Shivan Zombie

Gravedigger

When Gravedigger enters, you may return target creature card from your graveyard to your hand.

Soulless One

Soulless One's power and toughness are each equal to the number of Zombies on the battlefield plus the number of Zombie cards in all graveyards.

Bone Dancer

Whenever Bone Dancer attacks and isn't blocked, you may put the top creature card of defending player's graveyard onto the battlefield under your control. If you do, Bone Dancer assigns no combat damage this turn.

Nightscape Apprentice

{U}, {T}: Put target creature you control on top of its owner's library.
{R}, {T}: Target creature gains first strike until end of turn.

Dross Prowler

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Midnight Reaper

Whenever a nontoken creature you control dies, this creature deals 1 damage to you and you draw a card.

Walking Dead

Minotaur Abomination

Priest of the Haunted Edge

{T}, Sacrifice Priest of the Haunted Edge: Target creature gets -X/-X until end of turn, where X is the number of snow lands you control. Activate only as a sorcery.

Undead Warchief

Zombie spells you cast cost {1} less to cast.
Zombie creatures you control get +2/+1.

Nightscape Familiar

Blue spells and red spells you cast cost {1} less to cast.
{1}{B}: Regenerate Nightscape Familiar.

Nightscape Master

{U}{U}, {T}: Return target creature to its owner's hand.
{R}{R}, {T}: Nightscape Master deals 2 damage to target creature.

Mire Triton

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

Khabál Ghoul

At the beginning of each end step, put a +1/+1 counter on Khabál Ghoul for each creature that died this turn.

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.)

Gutless Ghoul

{1}, Sacrifice a creature: You gain 2 life.

Frankenstein's Monster

As Frankenstein's Monster enters, exile X creature cards from your graveyard. If you can't, put Frankenstein's Monster into its owner's graveyard instead of onto the battlefield. For each creature card exiled this way, Frankenstein's Monster enters with a +2/+0, +1/+1, or +0/+2 counter on it.

Tomb Tyrant

Other Zombies you control get +1/+1.
{2}{B}, {T}, Sacrifice a creature: Return a Zombie creature card at random from your graveyard to the battlefield. Activate only during your turn and only if there are at least three Zombie creature cards in your graveyard.

Undead Minotaur

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.)

Bog Raiders

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Contagious Nim

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Nightscape Battlemage

Kicker {2}{U} and/or {2}{R} (You may pay an additional {2}{U} and/or {2}{R} as you cast this spell.)
When Nightscape Battlemage enters, if it was kicked with its {2}{U} kicker, return up to two target nonblack creatures to their owners' hands.
When Nightscape Battlemage enters, if it was kicked with its {2}{R} kicker, destroy target land.

Havengul Lich

{1}: You may cast target creature card in a graveyard this turn. When you cast it this turn, Havengul Lich gains all activated abilities of that card until end of turn.

Hand of the Praetors

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Other creatures you control with infect get +1/+1.
Whenever you cast a creature spell with infect, target player gets a poison counter.

Highborn Ghoul

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Rotlung Reanimator

Whenever Rotlung Reanimator or another Cleric dies, create a 2/2 black Zombie creature token.

Order of Yawgmoth

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Whenever Order of Yawgmoth deals damage to a player, that player discards a card.

Coffin Queen

You may choose not to untap Coffin Queen during your untap step.
{2}{B}, {T}: Put target creature card from a graveyard onto the battlefield under your control. When Coffin Queen becomes untapped or you lose control of Coffin Queen, exile that creature.

Liliana, Dreadhorde General

Whenever a creature you control dies, draw a card.
+1: Create a 2/2 black Zombie creature token.
−4: Each player sacrifices two creatures of their choice.
−9: Each opponent chooses a permanent they control of each permanent type and sacrifices the rest.

Apprentice Necromancer

{B}, {T}, Sacrifice Apprentice Necromancer: Return target creature card from your graveyard to the battlefield. That creature gains haste. At the beginning of the next end step, sacrifice it.

Josu Vess, Lich Knight

Kicker {5}{B} (You may pay an additional {5}{B} as you cast this spell.)
Menace
When Josu Vess, Lich Knight enters, if it was kicked, create eight 2/2 black Zombie Knight creature tokens with menace.

Getting more of

Zombie Master

Other Zombie creatures have swampwalk. (They can't be blocked as long as defending player controls a Swamp.)
Other Zombies have "{B}: Regenerate this permanent."

Discordant Piper

When Discordant Piper dies, create a 0/1 white Goat creature token.

Champion of the Perished

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

Zombie Outlander

Dread Slaver

Whenever a creature dealt damage by Dread Slaver this turn dies, return it to the battlefield under your control. That creature is a black Zombie in addition to its other colors and types.

Cursed Minotaur

Menace (This creature can't be blocked except by two or more creatures.)

Dreadhorde Butcher

Haste
Whenever Dreadhorde Butcher deals combat damage to a player or planeswalker, put a +1/+1 counter on Dreadhorde Butcher.
When Dreadhorde Butcher dies, it deals damage equal to its power to any target.

Hollow Dogs

Whenever Hollow Dogs attacks, it gets +2/+0 until end of turn.

Deathspore Thallid

At the beginning of your upkeep, put a spore counter on Deathspore Thallid.
Remove three spore counters from Deathspore Thallid: Create a 1/1 green Saproling creature token.
Sacrifice a Saproling: Target creature gets -1/-1 until end of turn.