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.

Death's-Head Buzzard

Flying
When this creature dies, all creatures get -1/-1 until end of turn.

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.

The Darkness Crystal

Black spells you cast cost {1} less to cast.
If a nontoken creature an opponent controls would die, instead exile it and you gain 2 life.
{4}{B}{B}, {T}: Put target creature card exiled with The Darkness Crystal onto the battlefield tapped under your control with two additional +1/+1 counters on it.

Nausea

All creatures get -1/-1 until end of turn.

Feed the Swarm

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

Urborg, Tomb of Yawgmoth

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

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Caltrops

Whenever a creature attacks, this artifact deals 1 damage to it.

Make Obsolete

Creatures your opponents control get -1/-1 until end of turn.

Plague Mare

This creature can't be blocked by white creatures.
When this creature enters, creatures your opponents control get -1/-1 until end of turn.

Archfiend of Ifnir

Flying
Whenever you cycle or discard another card, put a -1/-1 counter on each creature your opponents control.
Cycling {2} ({2}, Discard this card: Draw a card.)

Mephitic Vapors

All creatures get -1/-1 until end of turn.
Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Massacre Wurm

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

Plague Spitter

At the beginning of your upkeep, this creature deals 1 damage to each creature and each player.
When this creature dies, it deals 1 damage to each creature and each player.

Corrosive Mentor

Black creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)

Pestilence

At the beginning of the end step, if no creatures are on the battlefield, sacrifice this enchantment.
{B}: This enchantment deals 1 damage to each creature and each player.

Sol Ring

Withering Torment

Destroy target creature or enchantment. You lose 2 life.

Kaervek, the Spiteful

Plague Engineer

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

V.A.T.S.

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Choose any number of target creatures with equal toughness. Destroy the chosen creatures.

Gruesome Realization

Choose one —
• You draw two cards and you lose 2 life.
• Creatures your opponents control get -1/-1 until end of turn.

Toxic Deluge

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

Cower in Fear

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.

Dread of Night

Glistening Deluge

All creatures get -1/-1 until end of turn. Creatures that are green and/or white get an additional -2/-2 until end of turn.

Poison the Waters

Choose one —
• All creatures get -1/-1 until end of turn.
• Target player reveals their hand. You choose an artifact or creature card from it. That player discards that card.

Disciple of Tevesh Szat

{T}: Target creature gets -1/-1 until end of turn.
{4}{B}{B}, {T}, Sacrifice this creature: Target creature gets -6/-6 until end of turn.

Screams from Within

Enchant creature
Enchanted creature gets -1/-1.
When enchanted creature dies, return this card from your graveyard to the battlefield.

Neutralize the Guards

Creatures target opponent controls get -1/-1 until end of turn. Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Maha, Its Feathers Night

Flying, trample
Ward—Discard a card.
Creatures your opponents control have base toughness 1.

Jet Medallion

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

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

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.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

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.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

The Black Breath

Creatures your opponents control get -1/-1 until end of turn. The Ring tempts you.

Night Clubber

When this creature enters, creatures your opponents control get -1/-1 until end of turn.
Blitz {2}{B} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik.

Shrivel

Cabal Coffers

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

Engineered Plague

As this enchantment enters, choose a creature type.
All creatures of the chosen type get -1/-1.

Carnifex Demon

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

Curse of Death's Hold

Enchant player
Creatures enchanted player controls get -1/-1.

Harbinger of Night

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

Ambulatory Edifice

When this creature enters, you may pay 2 life. When you do, target creature gets -1/-1 until end of turn.

Night of Souls' Betrayal

Reliquary Tower

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

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}.

Dark Ritual

Mithril Coat

Flash
Indestructible
When Mithril Coat enters, attach it to target legendary creature you control.
Equipped creature has indestructible.
Equip {3}

Black Sun's Zenith

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

Suffocating Fumes

Creatures your opponents control get -1/-1 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Pack's Disdain

Choose a creature type. Target creature gets -1/-1 until end of turn for each permanent of the chosen type you control.

Festergloom

Nonblack creatures get -1/-1 until end of turn.

Let's Play a Game

Delirium — Choose one. If there are four or more card types among cards in your graveyard, choose one or more instead.
• Creatures your opponents control get -1/-1 until end of turn.
• Each opponent discards two cards.
• Each opponent loses 3 life and you gain 3 life.

Soul Snuffers

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

Illness in the Ranks

Noxious Field

Enchant land
Enchanted land has "{T}: This land deals 1 damage to each creature and each player."

Swamp

Plague Dogs

When this creature dies, all creatures get -1/-1 until end of turn.
{2}, Sacrifice this creature: Draw a card.

Outbreak

You may discard a Swamp card rather than pay this spell's mana cost.
Choose a creature type. All creatures of that type get -1/-1 until end of turn.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)