When Acererak the Archlich enters the battlefield, if you haven't completed Tomb of Annihilation, return Acererak the Archlich to its owner's hand and venture into the dungeon.
Whenever Acererak the Archlich attacks, for each opponent, you create a 2/2 black Zombie creature token unless that player sacrifices a creature.
5 /
5
{1}{U/B}{U/B}
Ashiok, Dream Render
Legendary Planeswalker - Ashiok
Spells and abilities your opponents control can't cause their controller to search their library.
-1: Target player mills four cards. Then exile each opponent's graveyard.
L:
5
{B}
Champion of the Perished
Creature - Zombie
Whenever another Zombie enters the battlefield under your control, put a +1/+1 counter on Champion of the Perished.
1 /
1
{3}{B}{B}
Dictate of Erebos
Enchantment
Flash
Whenever a creature you control dies, each opponent sacrifices a creature.
{1}{B}
Dreadhorde Invasion
Enchantment
At the beginning of your upkeep, you lose 1 life and amass Zombies 1. (Put a +1/+1 counter on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)
Whenever a Zombie token you control with power 6 or greater attacks, it gains lifelink until end of turn.
{1}{B}{B}{B}
Grave Pact
Enchantment
Whenever a creature you control dies, each other player sacrifices a creature.
{3}{B}{B}{B}
Mikaeus, the Unhallowed
Legendary Creature - Zombie Cleric
Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a Human deals damage to you, destroy it.
Other non-Human creatures you control get +1/+1 and have undying. (When a creature with undying 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.)
5 /
5
{3}{U}
Necroduality
Enchantment
Whenever a nontoken Zombie enters the battlefield under your control, create a token that's a copy of that creature.
{1}{B}
Shepherd of Rot
Creature - Zombie Cleric
{T}: Each player loses 1 life for each Zombie on the battlefield.
1 /
1
{3}{B}{B}
Sidisi, Undead Vizier
Legendary Creature - Zombie Naga
Deathtouch
Exploit (When this creature enters the battlefield, you may sacrifice a creature.)
When Sidisi, Undead Vizier exploits a creature, you may search your library for a card, put it into your hand, then shuffle.
4 /
6
{1}{B}{B}
Zombie Master
Creature - Zombie
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."