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.)

Golgari Signet

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.

Flourishing Defenses

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

Creakwood Liege

Other black creatures you control get +1/+1.
Other green creatures you control get +1/+1.
At the beginning of your upkeep, you may create a 1/1 black and green Worm creature token.

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.

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.)

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Maha, Its Feathers Night

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

Phyresis Outbreak

Each opponent gets a poison counter. Then each creature your opponents control gets -1/-1 until end of turn for each poison counter its controller has.

Splendid Agony

Distribute two -1/-1 counters among one or two target creatures.

Lethal Sting

As an additional cost to cast this spell, put a -1/-1 counter on a creature you control.
Destroy 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.)

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.

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Sol Ring

Torment of Venom

Put three -1/-1 counters on target creature. Its controller loses 3 life unless they sacrifice another nonland permanent of their choice or discard a card.

Blowfly Infestation

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

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Moldervine Reclamation

Whenever a creature you control dies, you gain 1 life and draw a card.

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.

Generous Patron

When Generous Patron enters, support 2. (Put a +1/+1 counter on each of up to two other target creatures.)
Whenever you put one or more counters on a creature you don't control, draw a card.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

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.)

Nest of Scarabs

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

Seshiro the Anointed

Other Snake creatures you control get +2/+2.
Whenever a Snake you control deals combat damage to a player, you may draw a card.

Hapatra, Vizier of Poisons

Whenever Hapatra, Vizier of Poisons deals combat damage to a player, you may put a -1/-1 counter on target creature.
Whenever you put one or more -1/-1 counters on a creature, create a 1/1 green Snake creature token with deathtouch.

Braids, Arisen Nightmare

At the beginning of your end step, you may sacrifice an artifact, creature, enchantment, land, or planeswalker. If you do, each opponent may sacrifice a permanent of their choice that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

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.

Corrupted Conviction

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Swamp

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.)

Village Rites

Vhati il-Dal

{T}: Until end of turn, target creature has base power 1 or base toughness 1.

Skinrender

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

Yawgmoth, Thran Physician

Protection from Humans
Pay 1 life, Sacrifice another creature: Put a -1/-1 counter on up to one target creature and draw a card.
{B}{B}, Discard a card: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Hapatra's Mark

Target creature you control gains hexproof until end of turn. Remove all -1/-1 counters from it. (A creature with hexproof can't be the target of spells or abilities your opponents control.)

Hooded Blightfang

Deathtouch
Whenever a creature you control with deathtouch attacks, each opponent loses 1 life and you gain 1 life.
Whenever a creature you control with deathtouch deals damage to a planeswalker, destroy that planeswalker.

Decimator Beetle

When Decimator Beetle enters, put a -1/-1 counter on target creature you control.
Whenever Decimator Beetle attacks, remove a -1/-1 counter from target creature you control and put a -1/-1 counter on up to one target creature defending player controls.

Poison-Tip Archer

Reach (This creature can block creatures with flying.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever another creature dies, each opponent loses 1 life.

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.

Obelisk Spider

Reach
Whenever Obelisk Spider 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.

Putrefy

Destroy target artifact or creature. It can't be regenerated.

Corrosive Mentor

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

Rottenmouth Viper

As an additional cost to cast this spell, you may sacrifice any number of nonland permanents. This spell costs {1} less to cast for each permanent sacrificed this way.
Whenever Rottenmouth Viper enters or attacks, put a blight counter on it. Then for each blight counter on it, each opponent loses 4 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Gift of the Viper

Put a +1/+1 counter, a reach counter, and a deathtouch counter on target creature. Untap it.

Fynn, the Fangbearer

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever a creature you control with deathtouch deals combat damage to a player, that player gets two poison counters. (A player with ten or more poison counters loses the game.)

Atomize

Destroy target nonland permanent. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Arcane Signet

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

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Devoted Druid

{T}: Add {G}.
Put a -1/-1 counter on Devoted Druid: Untap Devoted Druid.

Black Sun's Zenith

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

Soul Snuffers

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

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.

Command Tower

Bloodroot Apothecary

Toxic 2 (Players dealt combat damage by this creature also get two poison counters. A player with ten or more poison counters loses the game.)
When Bloodroot Apothecary enters, you and target opponent each create a Treasure token.
Whenever an opponent sacrifices a noncreature token, that player gets two poison counters.

Quillspike

{B/G}, Remove a -1/-1 counter from a creature you control: Quillspike gets +3/+3 until end of turn.

Forest

Pitiless Plunderer

Whenever another creature you control dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Crumbling Ashes

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

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.

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.

Sadistic Obsession

Enchant creature
Enchanted creature has "{B}, {T}: Put a -1/-1 counter on target creature."

Stinging Shot

Put three -1/-1 counters on target creature with flying.
Cycling {2} ({2}, Discard this card: Draw a card.)

Enduring Vitality

Vigilance
Creatures you control have "{T}: Add one mana of any color."
When Enduring Vitality dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Wickerbough Elder

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

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.

Fume Spitter

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

Channeler Initiate

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