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.)

Castle Locthwain

Castle Locthwain enters the battlefield tapped unless you control a Swamp.
{T}: Add {B}.
{1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.

Lord Skitter, Sewer King

Whenever another Rat enters the battlefield under your control, exile up to one target card from an opponent's graveyard.
At the beginning of combat on your turn, create a 1/1 black Rat creature token with "This creature can't block."

Rat Colony

Rat Colony gets +1/+0 for each other Rat you control.
A deck can have any number of cards named Rat Colony.

Bad Moon

Foul-Tongue Shriek

Target opponent loses 1 life for each attacking creature you control. You gain that much life.

Twisted Sewer-Witch

When Twisted Sewer-Witch enters the battlefield, create a 1/1 black Rat creature token with "This creature can't block." Then for each Rat you control, create a Wicked Role token attached to that Rat. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1. When this Aura is put into a graveyard, each opponent loses 1 life.)

Tangled Colony

Tangled Colony can't block.
When Tangled Colony dies, create X 1/1 black Rat creature tokens with "This creature can't block," where X is the amount of damage dealt to it this turn.

Icon of Ancestry

As Icon of Ancestry enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{3}, {T}: Look at the top three cards of your library. You may reveal a creature card of the chosen type from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Sol Ring

Basalt Monolith

Basalt Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap Basalt Monolith.

Cabal Coffers

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

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Locthwain Scorn

Target creature gets -3/-3 until end of turn. You gain 2 life.

Virtue of Persistence

At the beginning of your upkeep, put target creature card from a graveyard onto the battlefield under your control.

Virtue of Persistence // Locthwain Scorn

Kindred Dominance

Choose a creature type. Destroy all creatures that aren't of the chosen type.

Wave of Rats

Trample
When Wave of Rats dies, if it dealt combat damage to a player this turn, return it to the battlefield under its owner's control.
Blitz {4}{B} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Whisper of the Dross

Target creature gets -1/-1 until end of turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Vat Emergence

Put target creature card from a graveyard onto the battlefield under your control. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Chittering Skitterling

Corrupted — Sacrifice an artifact or creature: Draw a card. Activate only if an opponent has three or more poison counters and only once each turn.

Drainpipe Vermin

When Drainpipe Vermin dies, you may pay {B}. If you do, target player discards a card.

Gutter Skulk

Beacon of Unrest

Put target artifact or creature card from a graveyard onto the battlefield under your control. Shuffle Beacon of Unrest into its owner's library.

Skullclamp

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

Beseech the Queen

({2/B} can be paid with any two mana or with {B}. This card's mana value is 6.)
Search your library for a card with mana value less than or equal to the number of lands you control, reveal it, put it into your hand, then shuffle.

Darkness

Prevent all combat damage that would be dealt this turn.

Typhoid Rats

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

The Black Gate

As The Black Gate enters the battlefield, you may pay 3 life. If you don't, it enters the battlefield tapped.
{T}: Add {B}.
{1}{B}, {T}: Choose a player with the most life or tied for most life. Target creature can't be blocked by creatures that player controls this turn.

Gravepurge

Put any number of target creature cards from your graveyard on top of your library.
Draw a card.

Dread Presence

Whenever a Swamp enters the battlefield under your control, choose one —
• You draw a card and you lose 1 life.
• Dread Presence deals 2 damage to any target and you gain 2 life.

Vampiric Rites

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.

Diabolic Intent

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a card, put that card into your hand, then shuffle.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Expedition Map

{2}, {T}, Sacrifice Expedition Map: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Voracious Vermin

When Voracious Vermin enters the battlefield, create a 1/1 black Rat creature token with "This creature can't block."
Whenever another creature you control dies, put a +1/+1 counter on Voracious Vermin.

Crippling Fear

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

Lord Skitter's Blessing

When Lord Skitter's Blessing enters the battlefield, create a Wicked Role token attached to target creature you control. (Enchanted creature gets +1/+1. When this Aura is put into a graveyard, each opponent loses 1 life.)
At the beginning of your draw step, if you control an enchanted creature, you lose 1 life and you draw an additional card.

Plague of Vermin

Starting with you, each player may pay any amount of life. Repeat this process until no one pays life. Each player creates a 1/1 black Rat creature token for each 1 life they paid this way.

Pestilence Rats

Pestilence Rats's power is equal to the number of other Rats on the battlefield. (For example, as long as there are two other Rats on the battlefield, Pestilence Rats's power and toughness are 2/3.)

Nezumi Informant

When Nezumi Informant enters the battlefield, each opponent discards a card.

Nezumi Bone-Reader

{B}, Sacrifice a creature: Target player discards a card. Activate only as a sorcery.

Leechridden Swamp

({T}: Add {B}.)
Leechridden Swamp enters the battlefield tapped.
{B}, {T}: Each opponent loses 1 life. Activate only if you control two or more black permanents.

Crypt of Agadeem

Crypt of Agadeem enters the battlefield tapped.
{T}: Add {B}.
{2}, {T}: Add {B} for each black creature card in your graveyard.

Rancid Rats

Skulk (This creature can't be blocked by creatures with greater power.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Piper of the Swarm

Rats you control have menace.
{1}{B}, {T}: Create a 1/1 black Rat creature token.
{2}{B}{B}, {T}, Sacrifice three Rats: Gain control of target creature.

Bog Rats

Dark Ritual

Necrogen Communion

Enchant creature you control
Enchanted creature has toxic 2. (Players dealt combat damage by it also get two poison counters.)
When enchanted creature dies, return that card to the battlefield under your control.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Rotting Rats

When Rotting Rats enters the battlefield, each player discards a card.
Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Karumonix, the Rat King

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Other Rats you control have toxic 1.
When Karumonix enters the battlefield, look at the top five cards of your library. You may reveal any number of Rat cards from among them and put the revealed cards into your hand. Put the rest on the bottom of your library in a random order.

Stinging Study

You draw X cards and you lose X life, where X is the mana value of a commander you own on the battlefield or in the command zone.

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.)

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik, Son of Yawgmoth.

Vraska's Fall

Each opponent sacrifices a creature or planeswalker and gets a poison counter.

Vraska, Betrayal's Sting

Compleated ({B/P} can be paid with {B} or 2 life. If life was paid, this planeswalker enters with two fewer loyalty counters.)
0: You draw a card and you lose 1 life. Proliferate.
−2: Target creature becomes a Treasure artifact with "{T}, Sacrifice this artifact: Add one mana of any color" and loses all other card types and abilities.
−9: If target player has fewer than nine poison counters, they get a number of poison counters equal to the difference.

Swamp

Entomb

Search your library for a card, put that card into your graveyard, then shuffle.

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Gnat Miser

Each opponent's maximum hand size is reduced by one.

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.

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Ravenous Rats

When Ravenous Rats enters the battlefield, target opponent discards a card.

Throat Slitter

Ninjutsu {2}{B} ({2}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Throat Slitter deals combat damage to a player, destroy target nonblack creature that player controls.

Sign in Blood

Target player draws two cards and loses 2 life.

Septic Rats

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever Septic Rats attacks, if defending player is poisoned, it gets +1/+1 until end of turn.

Withering Boon

As an additional cost to cast this spell, pay 3 life.
Counter target creature spell.

Ayara, First of Locthwain

Whenever Ayara, First of Locthwain or another black creature enters the battlefield under your control, each opponent loses 1 life and you gain 1 life.
{T}, Sacrifice another black creature: Draw a card.

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.)

Graf Rats

At the beginning of combat on your turn, if you both own and control Graf Rats and a creature named Midnight Scavengers, exile them, then meld them into Chittering Host.

Intimidation

Creatures you control have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature.

Gravestorm

At the beginning of your upkeep, target opponent may exile a card from their graveyard. If that player doesn't, you may draw a card.

Ogre Slumlord

Whenever another nontoken creature dies, you may create a 1/1 black Rat creature token.
Rats you control have deathtouch.

Reliquary Tower

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

Glistening Oil

Enchant creature
Enchanted creature has infect.
At the beginning of your upkeep, put a -1/-1 counter on enchanted creature.
When Glistening Oil is put into a graveyard from the battlefield, return Glistening Oil to its owner's hand.

Lord Skitter's Butcher

When Lord Skitter's Butcher enters the battlefield, choose one —
• Create a 1/1 black Rat creature token with "This creature can't block."
• You may sacrifice another creature. If you do, scry 2, then draw a card.
• Creatures you control gain menace until end of turn.

Dark Petition

Search your library for a card, put that card into your hand, then shuffle.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, add {B}{B}{B}.

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Pack Rat

Pack Rat's power and toughness are each equal to the number of Rats you control.
{2}{B}, Discard a card: Create a token that's a copy of Pack Rat.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Bone Splinters

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Relentless Rats

Relentless Rats gets +1/+1 for each other creature on the battlefield named Relentless Rats.
A deck can have any number of cards named Relentless Rats.

Locust Miser

Each opponent's maximum hand size is reduced by two.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters the battlefield, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Coat of Arms

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

Aligned Hedron Network

When Aligned Hedron Network enters the battlefield, exile all creatures with power 5 or greater until Aligned Hedron Network leaves the battlefield. (Those creatures return under their owners' control.)

Wishclaw Talisman

Wishclaw Talisman enters the battlefield with three wish counters on it.
{1}, {T}, Remove a wish counter from Wishclaw Talisman: Search your library for a card, put it into your hand, then shuffle. An opponent gains control of Wishclaw Talisman. Activate only during your turn.

Ashcoat of the Shadow Swarm

Whenever Ashcoat of the Shadow Swarm attacks or blocks, other Rats you control get +X/+X until end of turn, where X is the number of Rats you control.
At the beginning of your end step, you may mill four cards. If you do, return up to two Rat creature cards from your graveyard to your hand. (To mill a card, put the top card of your library into your graveyard.)

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.

Ichor Rats

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Ichor Rats enters the battlefield, each player gets a poison counter.

Burglar Rat

When Burglar Rat enters the battlefield, each opponent discards a card.

Stunning Reversal

The next time you would lose the game this turn, instead draw seven cards and your life total becomes 1.
Exile Stunning Reversal.

Bojuka Bog

Bojuka Bog enters the battlefield tapped.
When Bojuka Bog enters the battlefield, exile target player's graveyard.
{T}: Add {B}.

Diabolic Tutor

Cover of Darkness

As Cover of Darkness enters the battlefield, choose a creature type.
Creatures of the chosen type have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

Thriving Rats

When Thriving Rats enters the battlefield, you get {E}{E} (two energy counters).
Whenever Thriving Rats attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it.

Patriarch's Bidding

Each player chooses a creature type. Each player returns all creature cards of a type chosen this way from their graveyard to the battlefield.