Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Yahenni's Expertise

All creatures get -3/-3 until end of turn.
You may cast a spell with mana value 3 or less from your hand without paying its mana cost.

Walking Ballista

Walking Ballista enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on Walking Ballista.
Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.

Reliquary Tower

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

Noosegraf Mob

Noosegraf Mob enters with five +1/+1 counters on it.
Whenever a player casts a spell, remove a +1/+1 counter from Noosegraf Mob. If you do, create a 2/2 black Zombie creature token.

Rise of the Dark Realms

Put all creature cards from all graveyards onto the battlefield under your control.

Carnifex Demon

Flying
Carnifex Demon enters with two -1/-1 counters on it.
{B}, Remove a -1/-1 counter from Carnifex Demon: Put a -1/-1 counter on each other creature.

Tarrian's Soulcleaver

Equipped creature has vigilance.
Whenever another artifact or creature is put into a graveyard from the battlefield, put a +1/+1 counter on equipped creature.
Equip {2}

Slaughter Specialist

When Slaughter Specialist enters, each opponent creates a 1/1 white Human creature token.
Whenever a creature an opponent controls dies, put a +1/+1 counter on Slaughter Specialist.

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.)

Mikaeus, the Unhallowed

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.)

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature.

Midnight Reaper

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

Noxious Ghoul

Whenever Noxious Ghoul or another Zombie enters, all non-Zombie creatures get -1/-1 until end of turn.

Genesis Chamber

Whenever a nontoken creature enters, if Genesis Chamber is untapped, that creature's controller creates a 1/1 colorless Myr artifact creature token.

Illness in the Ranks

Phyrexian Obliterator

Trample
Whenever a source deals damage to Phyrexian Obliterator, that source's controller sacrifices that many permanents.

Strixhaven Stadium

{T}: Add {C}. Put a point counter on Strixhaven Stadium.
Whenever a creature deals combat damage to you, remove a point counter from Strixhaven Stadium.
Whenever a creature you control deals combat damage to an opponent, put a point counter on Strixhaven Stadium. Then if it has ten or more point counters on it, remove them all and that player loses the game.

Crumbling Ashes

At the beginning of your upkeep, destroy target creature with a -1/-1 counter on it.

Strip Mine

{T}: Add {C}.
{T}, Sacrifice Strip Mine: Destroy target land.

Ghoulcaller Gisa

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

Blowfly Infestation

Whenever a creature dies, if it had a -1/-1 counter on it, put a -1/-1 counter on target creature.

Mutilate

All creatures get -1/-1 until end of turn for each Swamp you control.

Midnight Banshee

Wither (This deals damage to creatures in the form of -1/-1 counters.)
At the beginning of your upkeep, put a -1/-1 counter on each nonblack creature.

Sceptre of Eternal Glory

{T}: Add one mana of any color.
{T}: Add three mana of any one color. Activate only if you control three or more lands with the same name.

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.

Sudden Spoiling

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Until end of turn, creatures target player controls lose all abilities and have base power and toughness 0/2.

No Mercy

Whenever a creature deals damage to you, destroy it.

Slice from the Shadows

This spell can't be countered. (This includes by the ward ability.)
Target creature gets -X/-X until end of turn.

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Soul Snuffers

When Soul Snuffers enters, put a -1/-1 counter on each creature.

Ascendant Evincar

Flying (This creature can't be blocked except by creatures with flying or reach.)
Other black creatures get +1/+1.
Nonblack creatures get -1/-1.

Plague Engineer

Deathtouch
As Plague Engineer enters, choose a creature type.
Creatures of the chosen type your opponents control get -1/-1.

Massacre Girl, Known Killer

Menace
Creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls dies, if its toughness was less than 1, draw a card.

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.

Nirkana Revenant

Whenever you tap a Swamp for mana, add an additional {B}.
{B}: Nirkana Revenant gets +1/+1 until end of turn.

Glistening Oil

Enchant creature
Enchanted creature has infect.
At the beginning of your upkeep, put a -1/-1 counter on enchanted creature.
When Glistening Oil is put into a graveyard from the battlefield, return Glistening Oil to its owner's hand.

Massacre Girl

Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Thought Vessel

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Contagion Engine

When Contagion Engine enters, put a -1/-1 counter on each creature target player controls.
{4}, {T}: Proliferate twice. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Massacre Wurm

When Massacre Wurm enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.

Skinrender

When Skinrender enters, put three -1/-1 counters on target creature.

Nest of Scarabs

Whenever you put one or more -1/-1 counters on a creature, create that many 1/1 black Insect creature tokens.

Imp's Mischief

Change the target of target spell with a single target. You lose life equal to that spell's mana value.

Black Sun's Zenith

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Massacre

If an opponent controls a Plains and you control a Swamp, you may cast this spell without paying its mana cost.
All creatures get -2/-2 until end of turn.

Swamp

Dark Ritual

Homeward Path

{T}: Add {C}.
{T}: Each player gains control of all creatures they own.

The Meathook Massacre

When The Meathook Massacre enters, each creature gets -X/-X until end of turn.
Whenever a creature you control dies, each opponent loses 1 life.
Whenever a creature an opponent controls dies, you gain 1 life.

Dismember

({B/P} can be paid with either {B} or 2 life.)
Target creature gets -5/-5 until end of turn.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Grave Titan

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

Incremental Blight

Put a -1/-1 counter on target creature, two -1/-1 counters on another target creature, and three -1/-1 counters on a third target creature.

Sol Ring

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.)

Kaervek, the Spiteful

Spitting Dilophosaurus

Whenever Spitting Dilophosaurus enters or attacks, put a -1/-1 counter on up to one target creature.
Creatures your opponents control with -1/-1 counters on them can't block.

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Necroskitter

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls with a -1/-1 counter on it dies, you may return that card to the battlefield under your control.

Jet Medallion

Black spells you cast cost {1} less to cast.

Grim Affliction

Put a -1/-1 counter on target creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Harbinger of Night

At the beginning of your upkeep, put a -1/-1 counter on each creature.

Drana, Liberator of Malakir

Flying, first strike
Whenever Drana, Liberator of Malakir deals combat damage to a player, put a +1/+1 counter on each attacking creature you control.