Swarmyard

{T}: Add {C}.
{T}: Regenerate target Insect, Rat, Spider, or Squirrel. (The next time it would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

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.)

Swarm of Rats

Swarm of Rats's power is equal to the number of Rats you control.

Cover of Darkness

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

Drainpipe Vermin

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

Contamination

At the beginning of your upkeep, sacrifice Contamination unless you sacrifice a creature.
If a land is tapped for mana, it produces {B} instead of any other type and amount.

Guildless Commons

Guildless Commons enters tapped.
When Guildless Commons enters, return a land you control to its owner's hand.
{T}: Add {C}{C}.

Vampiric Rites

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

Stabwhisker the Odious

At the beginning of each opponent's upkeep, that player loses 1 life for each card fewer than three in their hand.

Nezumi Shortfang

{1}{B}, {T}: Target opponent discards a card. Then if that player has no cards in hand, flip Nezumi Shortfang.

Nezumi Shortfang // Stabwhisker the Odious

Crypt Rats

{X}: Crypt Rats deals X damage to each creature and each player. Spend only black mana on X.

Door of Destinies

As Door of Destinies enters, choose a creature type.
Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies.
Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.

Vanquisher's Banner

As Vanquisher's Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Ruin Rat

Deathtouch
When Ruin Rat dies, exile target card from an opponent's graveyard.

Gnat Miser

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

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.

Stronghold Rats

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Stronghold Rats deals combat damage to a player, each player discards a card.

Scrib Nibblers

{T}: Exile the top card of target player's library. If it's a land card, you gain 1 life.
Landfall — Whenever a land you control enters, you may untap Scrib Nibblers.

Damnation

Destroy all creatures. They can't be regenerated.

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Attrition

{B}, Sacrifice a creature: Destroy target nonblack creature.

Feed the Swarm

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

Rats' Feast

Exile X target cards from a single graveyard.

Kindred Dominance

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

Bojuka Bog

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

Everglades

Everglades enters tapped.
When Everglades enters, sacrifice it unless you return an untapped Swamp you control to its owner's hand.
{T}: Add {C}{B}.

Diseased Vermin

Whenever Diseased Vermin deals combat damage to a player, put an infection counter on it.
At the beginning of your upkeep, Diseased Vermin deals X damage to target opponent previously dealt damage by it, where X is the number of infection counters on it.

Marrow-Gnawer

All Rats have fear.
{T}, Sacrifice a Rat: Create X 1/1 black Rat creature tokens, where X is the number of Rats you control.

Bastion of Remembrance

When Bastion of Remembrance enters, create a 1/1 white Human Soldier creature token.
Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

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.)

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.

Gruesome Fate

Each opponent loses 1 life for each creature you control.

Gate to Phyrexia

Sacrifice a creature: Destroy target artifact. Activate only during your upkeep and only once each turn.

Castle Locthwain

Castle Locthwain enters 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.

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.

Typhoid Rats

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

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Witch's Cauldron

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

Exsanguinate

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

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Obelisk of Urd

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
As Obelisk of Urd enters, choose a creature type.
Creatures you control of the chosen type get +2/+2.

Sol Ring

Ink-Eyes, Servant of Oni

Ninjutsu {3}{B}{B} ({3}{B}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Ink-Eyes, Servant of Oni deals combat damage to a player, you may put target creature card from that player's graveyard onto the battlefield under your control.
{1}{B}: Regenerate Ink-Eyes.

Stoneforge Masterwork

Equipped creature gets +1/+1 for each other creature you control that shares a creature type with it.
Equip {2}

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Oversold Cemetery

At the beginning of your upkeep, if you have four or more creature cards in your graveyard, you may return target creature card from your graveyard to your hand.

Thran Lens

Forever Young

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

Rabid Rats

{T}: Target blocking creature gets -1/-1 until end of turn.

Mire in Misery

Each opponent sacrifices a creature or enchantment of their choice.

Infected Vermin

{2}{B}: Infected Vermin deals 1 damage to each creature and each player.
Threshold — {3}{B}: Infected Vermin deals 3 damage to each creature and each player. Activate only if seven or more cards are in your graveyard.

Eat to Extinction

Exile target creature or planeswalker. Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Rat Colony

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

Locust Miser

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

Ravenous Rats

When Ravenous Rats enters, target opponent discards a card.

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.)

Ogre Slumlord

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

Crypt Incursion

Exile all creature cards from target player's graveyard. You gain 3 life for each card exiled this way.

Witch's Cottage

({T}: Add {B}.)
Witch's Cottage enters tapped unless you control three or more other Swamps.
When Witch's Cottage enters untapped, you may put target creature card from your graveyard on top of your library.

Koskun Falls

At the beginning of your upkeep, sacrifice Koskun Falls unless you tap an untapped creature you control.
Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Chittering Witch

When Chittering Witch enters, create a number of 1/1 black Rat creature tokens equal to the number of opponents you have.
{1}{B}, Sacrifice a creature: Target creature gets -2/-2 until end of turn.

Burglar Rat

When this creature enters, each opponent discards a card.

Polluted Bonds

Whenever a land an opponent controls enters, that player loses 2 life and you gain 2 life.

Rotting Rats

When Rotting Rats enters, 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.)

Mortuary Mire

Mortuary Mire enters tapped.
When Mortuary Mire enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Ratcatcher

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
At the beginning of your upkeep, you may search your library for a Rat card, reveal it, put it into your hand, then shuffle.

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}

Lab Rats

Buyback {4} (You may pay an additional {4} as you cast this spell. If you do, put this card into your hand as it resolves.)
Create a 1/1 black Rat creature token.

Swamp

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.