Arcane Signet

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

Soul Snuffers

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

Serrated Biskelion

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

Festering Mummy

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

Scar

Razor Swine

First strike
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Falkenrath Noble

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

Terminate

Destroy target creature. It can't be regenerated.

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.)

Sickle Ripper

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

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.

Village Rites

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

Fallen Ferromancer

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

Mahadi, Emporium Master

At the beginning of your end step, create a Treasure token for each creature that died this turn. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Havengul Vampire

Whenever this creature deals combat damage to a player, put a +1/+1 counter on it.
Whenever another creature dies, put a +1/+1 counter on this creature.

Attempted Murder

Choose target creature. Roll X six-sided dice. For each even result, put two -1/-1 counters on that creature. For each odd result, create a 1/2 blue Bird creature token with flying named Storm Crow.

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.

Typhoid Rats

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Iron Myr

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.

Thrill-Kill Assassin

Deathtouch
Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

Cinder Barrens

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

Foreboding Ruins

As this land enters, you may reveal a Swamp or Mountain card from your hand. If you don't, this land enters tapped.
{T}: Add {B} or {R}.

Lagomos, Hand of Hatred

At the beginning of combat on your turn, create a 2/1 red Elemental creature token with trample and haste. Sacrifice it at the beginning of the next end step.
{T}: Search your library for a card, put it into your hand, then shuffle. Activate only if five or more creatures died this turn.

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

Puncture Bolt

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

Rakdos Cackler

Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

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.)

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.)

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.

Bloodfell Caves

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {R}.

Plague Stinger

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Harbinger of Night

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

Sol Ring

Ashenmoor Liege

Other black creatures you control get +1/+1.
Other red creatures you control get +1/+1.
Whenever this creature becomes the target of a spell or ability an opponent controls, that player loses 4 life.

Blur of Blades

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

Splendid Agony

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

Murderous Redcap

When this creature 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.)

Stigma Lasher

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

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.

Flesh-Eater Imp

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Sacrifice a creature: Flesh-Eater Imp gets +1/+1 until end of turn.

Geothermal Bog

({T}: Add {B} or {R}.)
This land enters tapped.

Blasphemous Act

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

Mountain

Orzhov Enforcer

Deathtouch
Afterlife 1 (When this creature dies, create a 1/1 white and black Spirit creature token with flying.)

Rakdos Cluestone

{T}: Add {B} or {R}.
{B}{R}, {T}, Sacrifice this artifact: Draw a card.

Reaper of Sheoldred

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever a source deals damage to this creature, that source's controller gets a poison counter.

Blowfly Infestation

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

Rakdos Charm

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

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.

Corrosive Mentor

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

Fume Spitter

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

Skinrender

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

Volt Charge

Volt Charge deals 3 damage to any target. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Soulstinger

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

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 this creature dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Merciless Javelineer

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

Leaden Myr

Nest of Scarabs

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

Smoldering Marsh

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

Rakdos Signet

Virulent Wound

Put a -1/-1 counter on target creature. When that creature dies this turn, its controller gets a poison counter.

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.)

Black Sun's Zenith

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

Flayer of the Hatebound

Undying (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.)
Whenever this creature or another creature enters from your graveyard, that creature deals damage equal to its power to any target.

Retribution

Choose two target creatures controlled by the same opponent. That player chooses and sacrifices one of those creatures. Put a -1/-1 counter on the other.

Swamp

Hired Poisoner

Hateflayer

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

Contagious Nim

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Malakir Cullblade

Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature.

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.

Persist

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