Swamp

Army of the Damned

Create thirteen tapped 2/2 black Zombie creature tokens.
Flashback {7}{B}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Headless Rider

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

Island

Endless Ranks of the Dead

At the beginning of your upkeep, create X 2/2 black Zombie creature tokens, where X is half the number of Zombies you control, rounded down.

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.

Crowded Crypt

{T}: Add {B}.
Whenever a creature you control dies, put a corpse counter on this artifact.
{4}{B}{B}, {T}, Sacrifice this artifact: Create a 2/2 black Zombie creature token with decayed for each corpse counter on this artifact. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)

Cleaver Skaab

{3}, {T}, Sacrifice another Zombie: Create two tokens that are copies of the sacrificed creature.

Wand of Orcus

Whenever equipped creature attacks or blocks, it and Zombies you control gain deathtouch until end of turn.
Whenever equipped creature deals combat damage to a player, create that many 2/2 black Zombie creature tokens.
Equip {3}

Gravecrawler

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

Open the Graves

Whenever a nontoken creature you control dies, create a 2/2 black Zombie creature token.

Tormod, the Desecrator

Whenever one or more cards leave your graveyard, create a tapped 2/2 black Zombie creature token.
Partner (You can have two commanders if both have partner.)

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.

Grave Titan

Deathtouch
Whenever this creature enters or attacks, create two 2/2 black Zombie creature tokens.

Ghoulcaller Gisa

{B}, {T}, Sacrifice another creature: Create X 2/2 black Zombie creature tokens, where X is the sacrificed creature's power.

Curse of Disturbance

Enchant player
Whenever enchanted player is attacked, create a 2/2 black Zombie creature token. Each opponent attacking that player does the same.