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.)

Soulstinger

When Soulstinger enters the battlefield, 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.

Bedevil

Destroy target artifact, creature, or planeswalker.

Deathbringer Thoctar

Whenever another creature dies, you may put a +1/+1 counter on Deathbringer Thoctar.
Remove a +1/+1 counter from Deathbringer Thoctar: It deals 1 damage to any target.

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.

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.

Spread the Sickness

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

Hex Parasite

{X}{B/P}: Remove up to X counters from target permanent. For each counter removed this way, Hex Parasite gets +1/+0 until end of turn. ({B/P} can be paid with either {B} or 2 life.)

Skinrender

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

Ashenmoor Liege

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

Graven Cairns

{T}: Add {C}.
{B/R}, {T}: Add {B}{B}, {B}{R}, or {R}{R}.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Reliquary Tower

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

Blight Sickle

Equipped creature gets +1/+0 and has wither. (It deals damage to creatures in the form of -1/-1 counters.)
Equip {2}

Skullclamp

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

Burnished Hart

{3}, Sacrifice Burnished Hart: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Luxury Suite

Luxury Suite enters the battlefield tapped unless you have two or more opponents.
{T}: Add {B} or {R}.

Soul Snuffers

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

Swamp

Bloodfell Caves

Bloodfell Caves enters the battlefield tapped.
When Bloodfell Caves enters the battlefield, you gain 1 life.
{T}: Add {B} or {R}.

Puncture Blast

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Puncture Blast deals 3 damage to any target.

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.

Sol Ring

Grim Return

Choose target creature card in a graveyard that was put there from the battlefield this turn. Put that card onto the battlefield under your control.

Torment of Venom

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

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.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

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.

Tainted Strike

Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Grim Poppet

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

Phyrexian Crusader

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

Contagion Engine

When Contagion Engine enters the battlefield, 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.)

Dictate of the Twin Gods

Flash
If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Nest of Scarabs

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

Corrosive Mentor

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

Massacre Girl

Menace
When Massacre Girl enters the battlefield, 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.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Thought Vessel

Crumbling Ashes

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

Ribbons

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Each opponent loses X life.

Cut // Ribbons

Smoldering Marsh

({T}: Add {B} or {R}.)
Smoldering Marsh enters the battlefield tapped unless you control two or more basic lands.

Grief Tyrant

Grief Tyrant enters the battlefield with four -1/-1 counters on it.
When Grief Tyrant dies, put a -1/-1 counter on target creature for each -1/-1 counter on Grief Tyrant.

Leaden Myr

Arcane Signet

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

Fists of the Demigod

Enchant creature
As long as enchanted creature is black, it gets +1/+1 and has wither. (It deals damage to creatures in the form of -1/-1 counters.)
As long as enchanted creature is red, it gets +1/+1 and has first strike.

Blasphemous Act

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

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.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Rakdos Signet

Bloodstained Mire

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Mountain

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.

Sword of Truth and Justice

Equipped creature gets +2/+2 and has protection from white and from blue.
Whenever equipped creature deals combat damage to a player, put a +1/+1 counter on a creature you control, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Equip {2}

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Blowfly Infestation

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

Banewhip Punisher

When Banewhip Punisher enters the battlefield, 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.

Puppeteer Clique

Flying
When Puppeteer Clique enters the battlefield, put target creature card from an opponent's graveyard onto the battlefield under your control. It gains haste. At the beginning of your next end step, exile it.
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.)

Blood Crypt

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

Lockjaw Snapper

Wither (This deals damage to creatures in the form of -1/-1 counters.)
When Lockjaw Snapper dies, put a -1/-1 counter on each creature with a -1/-1 counter on it.

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.

Temple of Malice

Temple of Malice enters the battlefield tapped.
When Temple of Malice enters the battlefield, scry 1.
{T}: Add {B} or {R}.

Sheoldred, Whispering One

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
At the beginning of your upkeep, return target creature card from your graveyard to the battlefield.
At the beginning of each opponent's upkeep, that player sacrifices a creature.

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.)

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.

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent or discards a card.

Warstorm Surge

Whenever a creature enters the battlefield under your control, it deals damage equal to its power to any target.

Dragonskull Summit

Dragonskull Summit enters the battlefield tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Iron Myr

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.

Carnifex Demon

Flying
Carnifex Demon enters the battlefield 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.

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Canyon Slough

({T}: Add {B} or {R}.)
Canyon Slough enters the battlefield tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Command Tower

Contagion Clasp

When Contagion Clasp enters the battlefield, 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.)

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.)

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.)

Black Sun's Zenith

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

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.

Chandra's Ignition

Target creature you control deals damage equal to its power to each other creature and each opponent.