Feed the Swarm

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

The Scorpion God

Whenever a creature with a -1/-1 counter on it dies, draw a card.
{1}{B}{R}: Put a -1/-1 counter on another target creature.
When The Scorpion God dies, return it to its owner's hand at the beginning of the next end step.

Contagion Clasp

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

Forgotten Cave

Forgotten Cave enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Plague Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{T}: Add {C}.

Lightning Greaves

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

Soul Snuffers

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

Iron Myr

Rakdos Carnarium

Rakdos Carnarium enters tapped.
When Rakdos Carnarium enters, return a land you control to its owner's hand.
{T}: Add {B}{R}.

Artifact Blast

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.

Command Tower

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

Nest of Scarabs

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

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.)

Charcoal Diamond

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

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.

Battle at the Bridge

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Target creature gets -X/-X until end of turn. You gain X life.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Kaervek the Merciless

Whenever an opponent casts a spell, Kaervek the Merciless deals damage equal to that spell's mana value to any target.

Searstep Pathway

Blightstep Pathway

Blightstep Pathway // Searstep Pathway

Hateflayer

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{2}{R}, {Q}: Hateflayer deals damage equal to its power to any target. ({Q} is the untap symbol.)

Mortuary Mire

Mortuary Mire enters tapped.
When Mortuary Mire enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Ammit Eternal

Afflict 3 (Whenever this creature becomes blocked, defending player loses 3 life.)
Whenever an opponent casts a spell, put a -1/-1 counter on Ammit Eternal.
Whenever Ammit Eternal deals combat damage to a player, remove all -1/-1 counters from it.

Erebos's Intervention

Choose one —
• Target creature gets -X/-X until end of turn. You gain X life.
• Exile up to twice X target cards from graveyards.

Malakir Mire

Malakir Mire enters tapped.
{T}: Add {B}.

Malakir Rebirth

Choose target creature. You lose 2 life. Until end of turn, that creature gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Malakir Rebirth // Malakir Mire

Curse of Death's Hold

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

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.

Arcane Signet

Phyrexian Plaguelord

{T}, Sacrifice Phyrexian Plaguelord: Target creature gets -4/-4 until end of turn.
Sacrifice a creature: Target creature gets -1/-1 until end of turn.

Stigma Lasher

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever Stigma Lasher deals damage to a player, that player can't gain life for the rest of the game.

Everlasting Torment

Players can't gain life.
Damage can't be prevented.
All damage is dealt as though its source had wither. (A source with wither deals damage to creatures in the form of -1/-1 counters.)

Talisman of Indulgence

{T}: Add {C}.
{T}: Add {B} or {R}. Talisman of Indulgence deals 1 damage to you.

Thran Dynamo

Murderous Redcap

When Murderous Redcap enters, it deals damage equal to its power to any target.
Persist (When this creature 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.)

Kulrath Knight

Flying
Wither (This deals damage to creatures in the form of -1/-1 counters.)
Creatures your opponents control with counters on them can't attack or block.

Rakdos Charm

Choose one —
• Exile target player's graveyard.
• Destroy target artifact.
• Each creature deals 1 damage to its controller.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Soulstinger

When Soulstinger enters, put two -1/-1 counters on target creature you control.
When Soulstinger dies, you may put a -1/-1 counter on target creature for each -1/-1 counter on Soulstinger.

Ichor Rats

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Ichor Rats enters, each player gets a poison counter.

Rakdos Signet

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Harbinger of Night

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

Corrosive Mentor

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

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Jaya's Immolating Inferno

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Jaya's Immolating Inferno deals X damage to each of up to three targets.

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.

Kolaghan's Command

Choose two —
• Return target creature card from your graveyard to your hand.
• Target player discards a card.
• Destroy target artifact.
• Kolaghan's Command deals 2 damage to any target.

Core Prowler

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Core Prowler dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Necropede

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Necropede dies, you may put a -1/-1 counter on target creature.

Serrated Biskelion

{T}: Put a -1/-1 counter on Serrated Biskelion and a -1/-1 counter on target creature.

Plague Engineer

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

Soul-Scar Mage

Prowess
If a source you control would deal noncombat damage to a creature an opponent controls, put that many -1/-1 counters on that creature instead.

Thriving Moor

Thriving Moor enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

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.

Oubliette

When Oubliette enters, target creature phases out until Oubliette leaves the battlefield. Tap that creature as it phases in this way. (Auras and Equipment phase out with it. While permanents are phased out, they're treated as though they don't exist.)

Swamp

Blowfly Infestation

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

Sol Ring

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.

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.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Skinrender

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

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Festering Mummy

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

Dusk Urchins

Whenever Dusk Urchins attacks or blocks, put a -1/-1 counter on it.
When Dusk Urchins dies, draw a card for each -1/-1 counter on it.

Azra Oddsmaker

At the beginning of combat on your turn, you may discard a card. If you do, choose a creature. Whenever that creature deals combat damage to a player this turn, you draw two cards.

Castle Locthwain

Castle Locthwain enters tapped unless you control a Swamp.
{T}: Add {B}.
{1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.

Grim Poppet

Grim Poppet enters with three -1/-1 counters on it.
Remove a -1/-1 counter from Grim Poppet: Put a -1/-1 counter on another target creature.

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.

Mountain

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Barren Moor

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

Scavenger Grounds

{T}: Add {C}.
{2}, {T}, Sacrifice a Desert: Exile all graveyards.

Crumbling Ashes

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

Black Sun's Zenith

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