Archfiend of Depravity

Flying
At the beginning of each opponent's end step, that player chooses up to two creatures they control, then sacrifices the rest.

Necrogen Communion

Enchant creature you control
Enchanted creature has toxic 2. (Players dealt combat damage by it also get two poison counters.)
When enchanted creature dies, return that card to the battlefield under your control.

Vraska's Fall

Each opponent sacrifices a creature or planeswalker and gets a poison counter.

Swamp

Pacifism

Enchant creature
Enchanted creature can't attack or block.

Farbog Revenant

Skulk (This creature can't be blocked by creatures with greater power.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Recover

Return target creature card from your graveyard to your hand.
Draw a card.

Sungold Barrage

Destroy target creature with toughness 4 or greater.

Tribute to Hunger

Target opponent sacrifices a creature. You gain life equal to that creature's toughness.

Memorial to Folly

Memorial to Folly enters tapped.
{T}: Add {B}.
{2}{B}, {T}, Sacrifice Memorial to Folly: Return target creature card from your graveyard to your hand.

Infectious Inquiry

You draw two cards and you lose 2 life. Each opponent gets a poison counter.

Scoured Barrens

Scoured Barrens enters tapped.
When Scoured Barrens enters, you gain 1 life.
{T}: Add {W} or {B}.

Chittering Harvester

Mutate {4}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, each opponent sacrifices a creature.

Revenant

Flying
Revenant's power and toughness are each equal to the number of creature cards in your graveyard.

Chaplain's Blessing

Bound by Moonsilver

Enchant creature
Enchanted creature can't attack, block, or transform.
Sacrifice another permanent: Attach Bound by Moonsilver to target creature. Activate only as a sorcery and only once each turn.

Disenchant

Ruinous Path

Destroy target creature or planeswalker.
Awaken 4—{5}{B}{B} (If you cast this spell for {5}{B}{B}, also put four +1/+1 counters on target land you control and it becomes a 0/0 Elemental creature with haste. It's still a land.)

Sanitarium Skeleton

{2}{B}: Return Sanitarium Skeleton from your graveyard to your hand.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Rancid Rats

Skulk (This creature can't be blocked by creatures with greater power.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Ormendahl, Profane Prince

Westvale Abbey

{T}: Add {C}.
{5}, {T}, Pay 1 life: Create a 1/1 white and black Human Cleric creature token.
{5}, {T}, Sacrifice five creatures: Transform Westvale Abbey, then untap it.

Westvale Abbey // Ormendahl, Profane Prince

Nighthowler

Bestow {2}{B}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Nighthowler and enchanted creature each get +X/+X, where X is the number of creature cards in all graveyards.

Blightbelly Rat

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When Blightbelly Rat dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Dutiful Return

Return up to two target creature cards from your graveyard to your hand.

Whisper of the Dross

Target creature gets -1/-1 until end of turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Plains

Rottenheart Ghoul

When Rottenheart Ghoul dies, target player discards a card.

Immolating Glare

Karumonix, the Rat King

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Other Rats you control have toxic 1.
When Karumonix enters, look at the top five cards of your library. You may reveal any number of Rat cards from among them and put the revealed cards into your hand. Put the rest on the bottom of your library in a random order.

Typhoid Rats

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Erase

Dark Dabbling

Regenerate target creature. Draw a card. (The next time the creature would be destroyed this turn, it isn't. Instead tap it, remove all damage from it, and remove it from combat.)
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, also regenerate each other creature you control.

Ultimate Price

Liliana, Defiant Necromancer

+2: Each player discards a card.
−X: Return target nonlegendary creature card with mana value X from your graveyard to the battlefield.
−8: You get an emblem with "Whenever a creature dies, return it to the battlefield under your control at the beginning of the next end step."

Liliana, Heretical Healer

Lifelink
Whenever another nontoken creature you control dies, exile Liliana, Heretical Healer, then return her to the battlefield transformed under her owner's control. If you do, create a 2/2 black Zombie creature token.

Liliana, Heretical Healer // Liliana, Defiant Necromancer

Fleshbag Marauder

When Fleshbag Marauder enters, each player sacrifices a creature.

Chittering Skitterling

Corrupted — Sacrifice an artifact or creature: Draw a card. Activate only if an opponent has three or more poison counters and only once each turn.

Divine Verdict

Destroy target attacking or blocking creature.

Zealot's Conviction

Flash
Enchant creature
Enchanted creature gets +1/+1.
Corrupted — As long as an opponent has three or more poison counters, enchanted creature gets an additional +1/+0 and has first strike.

Vivisection Evangelist

Vigilance
Corrupted — When Vivisection Evangelist enters, if an opponent has three or more poison counters, destroy target creature or planeswalker an opponent controls.

Offer Immortality

Target creature gains deathtouch and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Rat Colony

Rat Colony gets +1/+0 for each other Rat you control.
A deck can have any number of cards named Rat Colony.

Atrocious Experiment

Target player mills two cards, draws two cards, and loses 2 life. (To mill a card, a player puts the top card of their library into their graveyard.)

Drown in Ichor

Target creature gets -4/-4 until end of turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Corpse Churn

Mill three cards, then you may return a creature card from your graveyard to your hand. (To mill three cards, put the top three cards of your library into your graveyard.)