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.

Arcane Signet

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

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.

Lord Skitter, Sewer King

Whenever another Rat you control enters, 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."

Swarm of Rats

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

Aid the Fallen

Choose one or both —
• Return target creature card from your graveyard to your hand.
• Return target planeswalker card from your graveyard to your hand.

Caged Sun

As Caged Sun enters, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Lord Skitter's Blessing

When Lord Skitter's Blessing enters, 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.

Bojuka Bog

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

Chittering Rats

When Chittering Rats enters, target opponent puts a card from their hand on top of their library.

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.)

Nezumi Ronin

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

Dark Ritual

Altar's Reap

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

Assassinate

Blight Grenade

Destroy target creature.
All creatures get -3/-3 until end of turn.

Leechridden Swamp

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

Howltooth Hollow

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Howltooth Hollow enters tapped.
{T}: Add {B}.
{B}, {T}: You may play the exiled card without paying its mana cost if each player has no cards in hand.

Aspect of Lamprey

Enchant creature you control
When Aspect of Lamprey enters, target opponent discards two cards.
Enchanted creature has lifelink.

Blightbelly Rat

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When Blightbelly Rat dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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.

Ruin Rat

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

Behold the Beyond

Discard your hand. Search your library for three cards, put them into your hand, then shuffle.

Kuro's Taken

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
{1}{B}: Regenerate Kuro's Taken.

Candy Grapple

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
Target creature gets -3/-3 until end of turn. If this spell was bargained, that creature gets -5/-5 until end of turn instead.

Agonizing Memories

Look at target player's hand and choose two cards from it. Put them on top of that player's library in any order.

Gnawing Vermin

When Gnawing Vermin enters, target player mills two cards.
When Gnawing Vermin dies, target creature you don't control gets -1/-1 until end of turn.

Ruthless Radrat

Squad—Exile four cards from your graveyard. (As an additional cost to cast this spell, you may pay its squad cost any number of times. When this creature enters, create that many tokens that are copies of it.)
Menace (This creature can't be blocked except by two or more creatures.)

Nashi, Moon Sage's Scion

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Nashi, Moon Sage's Scion deals combat damage to a player, exile the top card of each player's library. Until end of turn, you may play one of those cards. If you cast a spell this way, pay life equal to its mana value rather than paying its mana cost.

Drainpipe Vermin

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

Acidic Dagger

{4}, {T}: Whenever target creature deals combat damage to a non-Wall creature this turn, destroy that non-Wall creature. When the targeted creature leaves the battlefield this turn, sacrifice Acidic Dagger. Activate only before blockers are declared.

Aether Snap

Remove all counters from all permanents and exile all tokens.

Mukotai Ambusher

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Lifelink

Sinuous Vermin

{3}{B}{B}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
As long as Sinuous Vermin is monstrous, it has menace. (It can't be blocked except by two or more creatures.)

Amaranthine Wall

Defender
{2}: Amaranthine Wall gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Nezumi Prowler

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When Nezumi Prowler enters, target creature you control gains deathtouch and lifelink until end of turn.

Appetite for Brains

Target opponent reveals their hand. You choose a card from it with mana value 4 or greater and exile that card.

Lord Skitter's Butcher

When Lord Skitter's Butcher enters, 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.

Biting Rain

All creatures get -2/-2 until end of turn.
Madness {2}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Agonizing Remorse

Target opponent reveals their hand. You choose a nonland card from it or a card from their graveyard. Exile that card. You lose 1 life.

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.)

Certain Death

Destroy target creature. Its controller loses 2 life and you gain 2 life.

Hive of the Eye Tyrant

If you control two or more other lands, Hive of the Eye Tyrant enters tapped.
{T}: Add {B}.
{3}{B}: Until end of turn, Hive of the Eye Tyrant becomes a 3/3 black Beholder creature with menace and "Whenever this creature attacks, exile target card from defending player's graveyard." It's still a land.

Corpse Churn

Mill three cards, then you may return a creature card from your graveyard to your hand. (To mill three cards, put the top three cards of your library into your graveyard.)

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.)

Blood Curdle

Destroy target creature. Put a menace counter on a creature you control. (It can't be blocked except by two or more creatures.)

Desert of the Glorified

Desert of the Glorified enters tapped.
{T}: Add {B}.
Cycling {1}{B} ({1}{B}, Discard this card: Draw a card.)

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.

Army of the Damned

Create thirteen tapped 2/2 black Zombie creature tokens.
Flashback {7}{B}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Old Flitterfang

Flying
At the beginning of each end step, if a creature died this turn, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
{2}{B}, Sacrifice another creature or artifact: Old Flitterfang gets +2/+2 until end of turn.

Deathmask Nezumi

As long as you have seven or more cards in hand, Deathmask Nezumi gets +2/+1 and has fear. (It can't be blocked except by artifact creatures and/or black creatures.)

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.

Sol Ring

Gutter Skulk

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, 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.

Agatha's Soul Cauldron

You may spend mana as though it were mana of any color to activate abilities of creatures you control.
Creatures you control with +1/+1 counters on them have all activated abilities of all creature cards exiled with Agatha's Soul Cauldron.
{T}: Exile target card from a graveyard. When a creature card is exiled this way, put a +1/+1 counter on target creature you control.

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.

Swamp

Voracious Vermin

When Voracious Vermin enters, 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.

Bitter Downfall

This spell costs {3} less to cast if it targets a creature that was dealt damage this turn.
Destroy target creature. Its controller loses 2 life.

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, each player gets a poison counter.

Nezumi Informant

When Nezumi Informant enters, each opponent discards a card.

Barbed Wire

At the beginning of each player's upkeep, Barbed Wire deals 1 damage to that player.
{2}: Prevent the next 1 damage that would be dealt by Barbed Wire this turn.

Amorphous Axe

Equipped creature gets +3/+0 and is every creature type.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Crypt Rats

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

Alms of the Vein

Target opponent loses 3 life and you gain 3 life.
Madness {B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Afflict

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

Ossuary Rats

When Ossuary Rats enters, it deals X damage to target creature or planeswalker an opponent controls, where X is the number of creature cards in your graveyard.

Abnormal Endurance

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Aspect of Gorgon

Enchant creature
Enchanted creature gets +1/+3 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy it.)

Alchemist's Gift

Target creature gets +1/+1 and gains your choice of deathtouch or lifelink until end of turn. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it. Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Amulet of Vigor

Whenever a permanent you control enters tapped, untap it.

Nezumi Bone-Reader

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

Nezumi Bladeblesser

Nezumi Bladeblesser has deathtouch as long as you control an artifact.
Nezumi Bladeblesser has menace as long as you control an enchantment. (It can't be blocked except by two or more creatures.)

Rat Colony

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

Altar of Shadows

At the beginning of your first main phase, add {B} for each charge counter on Altar of Shadows.
{7}, {T}: Destroy target creature. Then put a charge counter on Altar of Shadows.

Agonizing Syphon

Agonizing Syphon deals 3 damage to any target and you gain 3 life.

Ancestral Vengeance

Enchant creature
When Ancestral Vengeance enters, put a +1/+1 counter on target creature you control.
Enchanted creature gets -1/-1.

Razortooth Rats

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)