Cat-Gator

Lifelink
When this creature enters, it deals damage equal to the number of Swamps you control to any target.

Auntie Ool, Cursewretch

Ward—Blight 2. (To blight 2, a player puts two -1/-1 counters on a creature they control.)
Whenever one or more -1/-1 counters are put on a creature, draw a card if you control that creature. If you don't control it, its controller loses 1 life.

Command Tower

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

Gnarlbark Elm

This creature enters with two -1/-1 counters on it.
{2}{B}, Remove two counters from this creature: Target creature gets -2/-2 until end of turn. Activate only as a sorcery.

Cower in Fear

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

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.)

Darkness Descends

Fungal Infection

Target creature gets -1/-1 until end of turn. Create a 1/1 green Saproling creature token.

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.

Erebos, God of the Dead

Indestructible
As long as your devotion to black is less than five, Erebos isn't a creature. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
Your opponents can't gain life.
{1}{B}, Pay 2 life: Draw a card.

Cultbrand Cinder

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

Dose of Dawnglow

Return target creature card from your graveyard to the battlefield. Then if it isn't your main phase, blight 2. (Put two -1/-1 counters on a creature you control.)

Black Sun's Zenith

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

Stomping Ground

({T}: Add {R} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Blood Crypt

({T}: Add {B} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Persistent Constrictor

At the beginning of each opponent's upkeep, they lose 1 life and you put a -1/-1 counter on up to one target creature they control.
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.)

Ignoble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {B}, {R}, or {G}.

Wickerbough Elder

This creature enters with a -1/-1 counter on it.
{G}, Remove a -1/-1 counter from this creature: Destroy target artifact or enchantment.

Rootbound Crag

This land enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

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.

Cartouche of Ambition

Enchant creature you control
When this Aura enters, you may put a -1/-1 counter on target creature.
Enchanted creature gets +1/+1 and has lifelink.

Deity of Scars

Trample
This creature enters with two -1/-1 counters on it.
{B/G}, Remove a -1/-1 counter from this creature: Regenerate this creature.

Arcane Signet

Festering Mummy

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

Woodland Cemetery

This land enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Soul Snuffers

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

Spire Garden

This land enters tapped unless you have two or more opponents.
{T}: Add {R} or {G}.

Dread Tiller

When this creature enters, put a -1/-1 counter on target creature.
Whenever a creature with a -1/-1 counter on it dies, you may put a land card from your hand or graveyard onto the battlefield tapped.

Forest

Nest of Scarabs

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

Whip of Erebos

Creatures you control have lifelink.
{2}{B}{B}, {T}: Return target creature card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step. If it would leave the battlefield, exile it instead of putting it anywhere else. Activate only as a sorcery.

Channeler Initiate

When this creature enters, put three -1/-1 counters on target creature you control.
{T}, Remove a -1/-1 counter from this creature: Add one mana of any color.

Aberrant Return

Put one, two, or three target creature cards from graveyards onto the battlefield under your control. Each of them enters with an additional -1/-1 counter on it.

Contagion Clasp

When this artifact 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.)

Baneclaw Marauder

Whenever this creature becomes blocked, each creature blocking it gets -1/-1 until end of turn.
Whenever a creature blocking this creature dies, that creature's controller loses 1 life.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Baneblade Scoundrel

Whenever this creature becomes blocked, each creature blocking it gets -1/-1 until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Baneblade Scoundrel // Baneclaw Marauder

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.

Sourbread Auntie

When this creature enters, you may blight 2. If you do, create two 1/1 black and red Goblin creature tokens. (To blight 2, put two -1/-1 counters on a creature you control.)

Swamp

Savage Lands

This land enters tapped.
{T}: Add {B}, {R}, or {G}.

Grim Poppet

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

Warren Torchmaster

At the beginning of combat on your turn, you may blight 1. When you do, target creature gains haste until end of turn. (To blight 1, put a -1/-1 counter on a creature you control.)

Banewhip Punisher

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

The Reaper, King No More

When The Reaper enters, put a -1/-1 counter on each of up to two target creatures.
Whenever a creature an opponent controls with a -1/-1 counter on it dies, you may put that card onto the battlefield under your control. Do this only once each turn.

Obelisk Spider

Reach
Whenever this creature deals combat damage to a creature, put a -1/-1 counter on that creature.
Whenever you put one or more -1/-1 counters on a creature, each opponent loses 1 life and you gain 1 life.

Terminate

Destroy target creature. It can't be regenerated.

Blightning

Blightning deals 3 damage to target player or planeswalker. That player or that planeswalker's controller discards two cards.

Crippling Blight

Enchant creature
Enchanted creature gets -1/-1 and can't block.

Persist

Return target nonlegendary creature card from your graveyard to the battlefield with a -1/-1 counter on it.

Defile

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

Blur of Blades

Put a -1/-1 counter on target creature. Blur of Blades deals 2 damage to that creature's controller.

Gruul Turf

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {R}{G}.

Brambleback Brute

This creature enters with two -1/-1 counters on it.
{1}{R}, Remove a counter from this creature: Target creature can't block this turn. Activate only as a sorcery.

Bogslither's Embrace

As an additional cost to cast this spell, blight 1 or pay {3}. (To blight 1, put a -1/-1 counter on a creature you control.)
Exile target creature.

Evolution Sage

Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Contagion Engine

When this artifact 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.)

Curse of Death's Hold

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

Blight Rot

Put four -1/-1 counters on target creature.

Mountain

Moonshadow

Menace
This creature enters with six -1/-1 counters on it.
Whenever one or more permanent cards are put into your graveyard from anywhere while this creature has a -1/-1 counter on it, remove a -1/-1 counter from this creature.

Dragonskull Summit

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Sol Ring

Smoldering Marsh

({T}: Add {B} or {R}.)
This land enters tapped unless you control two or more basic lands.

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.

Eternal Thirst

Enchant creature
Enchanted creature has lifelink and "Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature." (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Overgrown Tomb

({T}: Add {B} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Baleful Ammit

Lifelink
When this creature enters, put a -1/-1 counter on target creature you control.

Flourishing Defenses

Whenever a -1/-1 counter is put on a creature, you may create a 1/1 green Elf Warrior creature token.

Tree of Perdition

Defender
{T}: Exchange target opponent's life total with this creature's toughness.

Grave Venerations

When this enchantment enters, you become the monarch.
At the beginning of your end step, if you're the monarch, return up to one target creature card from your graveyard to your hand.
Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

Caustic Crawler

Landfall — Whenever a land you control enters, you may have target creature get -1/-1 until end of turn.

Cinder Glade

({T}: Add {R} or {G}.)
This land enters tapped unless you control two or more basic lands.

Liliana, Death Mage

+1: Return up to one target creature card from your graveyard to your hand.
−3: Destroy target creature. Its controller loses 2 life.
−7: Target opponent loses 2 life for each creature card in their graveyard.

Blowfly Infestation

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

Vernal Fen

({T}: Add {B} or {G}.)
This land enters tapped unless you control two or more basic lands.

Reliquary Tower

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

Clawing Torment

Enchant artifact or creature
As long as enchanted permanent is a creature, it gets -1/-1 and can't block.
Enchanted permanent has "At the beginning of your upkeep, you lose 1 life."

Skinrender

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

Eyeblight Assassin

When this creature enters, target creature an opponent controls gets -1/-1 until end of turn.

Boggart Mischief

When this enchantment enters, you may blight 1. If you do, create two 1/1 black and red Goblin creature tokens. (To blight 1, put a -1/-1 counter on a creature you control.)
Whenever a Goblin creature you control dies, each opponent loses 1 life and you gain 1 life.

Bile-Vial Boggart

When this creature dies, put a -1/-1 counter on up to one target creature.

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.

High Perfect Morcant

Whenever High Perfect Morcant or another Elf you control enters, each opponent blights 1. (They each put a -1/-1 counter on a creature they control.)
Tap three untapped Elves you control: Proliferate. Activate only as a sorcery. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)