Pestilence Demon

Flying
{B}: Pestilence Demon deals 1 damage to each creature and each player.

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.

Night's Whisper

Festergloom

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

Yahenni, Undying Partisan

Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni, Undying Partisan.
Sacrifice another creature: Yahenni gains indestructible until end of turn.

Dry Spell

Dry Spell deals 1 damage to each creature and each player.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Skinrender

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

Suffocating Fumes

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

Agate-Blade Assassin

Whenever Agate-Blade Assassin attacks, defending player loses 1 life and you gain 1 life.

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Ambition's Cost

You draw three cards and you lose 3 life.

Bonebind Orator

{3}{B}, Exile Bonebind Orator from your graveyard: Return another target creature card from your graveyard to your hand.

Black Sun's Zenith

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

Death's-Head Buzzard

Flying
When Death's-Head Buzzard dies, all creatures get -1/-1 until end of turn.

Drown in Sorrow

All creatures get -2/-2 until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Nausea

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

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Sign in Blood

Target player draws two cards and loses 2 life.

Liliana's Influence

Put a -1/-1 counter on each creature you don't control. You may search your library and/or graveyard for a card named Liliana, Death Wielder, reveal it, and put it into your hand. If you search your library this way, shuffle.

Sol Ring

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.)

Soul Snuffers

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

Gisa, Glorious Resurrector

If a creature an opponent controls would die, exile it instead.
At the beginning of your upkeep, put all creature cards exiled with Gisa, Glorious Resurrector onto the battlefield under your control. They gain decayed. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)

Marsh Casualties

Kicker {3} (You may pay an additional {3} as you cast this spell.)
Creatures target player controls get -1/-1 until end of turn. If this spell was kicked, those creatures get -2/-2 until end of turn instead.

Barren Moor

Barren Moor enters tapped.
{T}: Add {B}.
Cycling {B} ({B}, Discard this card: Draw a card.)

Night of Souls' Betrayal

The Black Breath

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

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.

Feed the Swarm

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

Night Clubber

When Night Clubber 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.)

Exsanguinate

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

Gravedig

Choose one —
• Target player creates a 2/2 black Zombie creature token.
• Return target creature card from your graveyard to your hand.
Entwine {2} (Choose both if you pay the entwine cost.)

Coiling Rebirth

Gift a card (You may promise an opponent a gift as you cast this spell. If you do, they draw a card before its other effects.)
Return target creature card from your graveyard to the battlefield. Then if the gift was promised and that creature isn't legendary, create a token that's a copy of that creature, except it's 1/1.

Champion's Helm

Equipped creature gets +2/+2.
As long as equipped creature is legendary, it has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Moonstone Eulogist

Flying
Whenever a creature an opponent controls dies, you create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice an artifact, put a +1/+1 counter on Moonstone Eulogist and you gain 1 life.

Fume Spitter

Sacrifice Fume Spitter: Put a -1/-1 counter on target creature.

Fell

Ifnir Deadlands

{T}: Add {C}.
{T}, Pay 1 life: Add {B}.
{2}{B}{B}, {T}, Sacrifice a Desert: Put two -1/-1 counters on target creature an opponent controls. Activate only as a sorcery.

Festering Mummy

When Festering Mummy dies, you may put a -1/-1 counter on target creature.

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.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Plague Mare

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

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Sangromancer

Flying
Whenever a creature an opponent controls dies, you may gain 3 life.
Whenever an opponent discards a card, you may gain 3 life.

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.

Pestilence

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

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Arms of Hadar

Creatures target player controls get -2/-2 until end of turn.

Morbid Opportunist

Whenever one or more other creatures die, draw a card. This ability triggers only once each turn.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Crypt Rats

{X}: Crypt Rats deals X damage to each creature and each player. Spend only black mana on X.

Kaervek, the Spiteful

Arcane Signet

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

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Ogre Slumlord

Whenever another nontoken creature dies, you may create a 1/1 black Rat creature token.
Rats you control have deathtouch.

Maha, Its Feathers Night

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

Starscape Cleric

Offspring {2}{B} (You may pay an additional {2}{B} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Flying
This creature can't block.
Whenever you gain life, each opponent loses 1 life.

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.

Malicious Eclipse

All creatures get -2/-2 until end of turn. If a creature an opponent controls would die this turn, exile it instead.

Make Obsolete

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

Stargaze

Look at twice X cards from the top of your library. Put X cards from among them into your hand and the rest into your graveyard. You lose X life.

Wick's Patrol

When Wick's Patrol enters, mill three cards. When you do, target creature an opponent controls gets -X/-X until end of turn, where X is the greatest mana value among cards in your graveyard.

Glidedive Duo

Flying
When Glidedive Duo enters, each opponent loses 2 life and you gain 2 life.

Grim Physician

When Grim Physician dies, target creature an opponent controls gets -1/-1 until end of turn.

Mutilate

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

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.

Savor

Target creature gets -2/-2 until end of turn. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Plague Spitter

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

Liliana, Death Wielder

+2: Put a -1/-1 counter on up to one target creature.
−3: Destroy target creature with a -1/-1 counter on it.
−10: Return all creature cards from your graveyard to the battlefield.

Curse of Death's Hold

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

Boggart Bog

As Boggart Bog enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.

Boggart Trawler

When Boggart Trawler enters, exile target player's graveyard.

Boggart Trawler // Boggart Bog

Minister of Pain

Exploit (When this creature enters, you may sacrifice a creature.)
When Minister of Pain exploits a creature, creatures your opponents control get -1/-1 until end of turn.

Banewhip Punisher

When Banewhip Punisher enters, you may put a -1/-1 counter on target creature.
{B}, Sacrifice Banewhip Punisher: Destroy target creature that has a -1/-1 counter on it.

Harvester of Souls

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever another nontoken creature dies, you may draw a card.

Grasping Dunes

{T}: Add {C}.
{1}, {T}, Sacrifice Grasping Dunes: Put a -1/-1 counter on target creature. Activate only as a sorcery.

Gruesome Realization

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

Falkenrath Noble

Flying
Whenever Falkenrath Noble or another creature dies, target player loses 1 life and you gain 1 life.

Shrivel

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Doomwake Giant

Constellation — Whenever Doomwake Giant or another enchantment you control enters, creatures your opponents control get -1/-1 until end of turn.

Bojuka Bog

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

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Blightbeetle

Protection from green (This creature can't be blocked, targeted, dealt damage, enchanted, or equipped by anything green.)
Creatures your opponents control can't have +1/+1 counters put on them.

Cower in Fear

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Restart Sequence

Freerunning {1}{B} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Return target creature card from your graveyard to the battlefield.