Merciless Javelineer

{2}, Discard a card: Put a -1/-1 counter on target creature. That creature can't block this turn.

Grim Strider

This creature gets -1/-1 for each card in your hand.

Defile

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

Scourge of Geier Reach

This creature gets +1/+1 for each creature your opponents control.

Barbed-Back Wurm

{B}: Target green creature blocking this creature gets -1/-1 until end of turn.

Rustrazor Butcher

First strike
Wither (This deals damage to creatures in the form of -1/-1 counters.)

Cower in Fear

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

Shrivel

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

Afflict

Target creature gets -1/-1 until end of turn.
Draw a card.

Snow-Covered Swamp

Shambling Goblin

When this creature dies, target creature an opponent controls gets -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.)

Crippling Blight

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

Ascendant Evincar

Flying (This creature can't be blocked except by creatures with flying or reach.)
Other black creatures get +1/+1.
Nonblack creatures get -1/-1.

Fungal Infection

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

Grief Tyrant

This creature enters with four -1/-1 counters on it.
When this creature dies, put a -1/-1 counter on target creature for each -1/-1 counter on this creature.

Quagmire Lamprey

Whenever this creature becomes blocked by a creature, put a -1/-1 counter on that creature.

Baleful Ammit

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

Suicidal Charge

Sacrifice this enchantment: Creatures your opponents control get -1/-1 until end of turn. Those creatures attack this turn if able.

Heartless Summoning

Creature spells you cast cost {2} less to cast.
Creatures you control get -1/-1.

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.

Festergloom

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

Eyeblight Assassin

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

Nest of Scarabs

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

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.

Grim Physician

Rix Maadi Guildmage

{B}{R}: Target blocking creature gets -1/-1 until end of turn.
{B}{R}: Target player who lost life this turn loses 1 life.

Festering Mummy

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

Curse of Death's Hold

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

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.)

Nefashu

Whenever this creature attacks, up to five target creatures each get -1/-1 until end of turn.

Sick and Tired

Two target creatures each get -1/-1 until end of turn.

Make Obsolete

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.

Blowfly Infestation

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

Weed-Pruner Poplar

At the beginning of your upkeep, target creature other than this creature gets -1/-1 until end of turn.

Viper's Kiss

Enchant creature
Enchanted creature gets -1/-1, and its activated abilities can't be activated.

Plagued Rusalka

{B}, Sacrifice a creature: Target creature gets -1/-1 until end of turn.

Scavenged Weaponry

Enchant creature
When this Aura enters, draw a card.
Enchanted creature gets +1/+1.

Death's-Head Buzzard

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

Crumbling Ashes

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

Skulduggery

Until end of turn, target creature you control gets +1/+1 and target creature an opponent controls gets -1/-1.

Necrologia

Cast this spell only during your end step.
As an additional cost to cast this spell, pay X life.
Draw X cards.

Scar

Drakestown Forgotten

This creature enters with X +1/+1 counters on it, where X is the number of creature cards in all graveyards.
{2}{B}, Remove a +1/+1 counter from this creature: Target creature gets -1/-1 until end of turn.

Plague Wight

Whenever this creature becomes blocked, each creature blocking it gets -1/-1 until end of turn.

Quag Sickness

Enchant creature
Enchanted creature gets -1/-1 for each Swamp you control.

Fume Spitter

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

Eyeblight Massacre

Non-Elf creatures get -2/-2 until end of turn.

Nausea

Mutilate

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

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.

Torture

Enchant creature
{1}{B}: Put a -1/-1 counter on enchanted creature.

Borrowed Malevolence

Escalate {2} (Pay this cost for each mode chosen beyond the first.)
Choose one or both —
• Target creature gets +1/+1 until end of turn.
• Target creature gets -1/-1 until end of turn.

Harbinger of Night

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

Puncture Bolt

Puncture Bolt deals 1 damage to target creature. Put a -1/-1 counter on that creature.

Cursed Flesh

Enchant creature
Enchanted creature gets -1/-1 and has fear. (It can't be blocked except by artifact creatures and/or black creatures.)

Nyxathid

As this creature enters, choose an opponent.
This creature gets -1/-1 for each card in the chosen player's hand.

Consumptive Goo

{2}{B}{B}: Target creature gets -1/-1 until end of turn. Put a +1/+1 counter on this creature.

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.)

Snow-Covered Mountain

Blind Creeper

Whenever a player casts a spell, this creature gets -1/-1 until end of turn.

Splendid Agony

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

Cabal Torturer

{B}, {T}: Target creature gets -1/-1 until end of turn.
Threshold — {3}{B}{B}, {T}: Target creature gets -2/-2 until end of turn. Activate only if seven or more cards are in your graveyard.

Blur of Blades

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

Sadistic Obsession

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

Dusk Urchins

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

Skinrender

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

Bogardan Lancer

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)
Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)

Serrated Arrows

This artifact enters with three arrowhead counters on it.
At the beginning of your upkeep, if there are no arrowhead counters on this artifact, sacrifice it.
{T}, Remove an arrowhead counter from this artifact: Put a -1/-1 counter on target creature.