Typhoid Rats

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

Chittering Rats

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

Voracious Fell Beast

Flying
When Voracious Fell Beast enters, each opponent sacrifices a creature of their choice. Create a Food token for each creature sacrificed this way. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Erebos, God of the Dead

Indestructible
As long as your devotion to black is less than five, Erebos isn't a creature. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
Your opponents can't gain life.
{1}{B}, Pay 2 life: Draw a card.

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.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Doom Blade

Locust Miser

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

Claim the Precious

Destroy target creature. The Ring tempts you.

Swarm of Rats

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

Ayara, First of Locthwain

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

Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.

Bojuka Bog

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

Terror

Destroy target nonartifact, nonblack creature. It can't be regenerated.

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}.

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.

Ravenous Rats

When Ravenous Rats enters, target opponent discards a card.

Bad Moon

Mask of Memory

Whenever equipped creature deals combat damage to a player, you may draw two cards. If you do, discard a card.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Swamp

Nezumi Cutthroat

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

Kindred Dominance

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

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.

Hero's Demise

Fetid Imp

Flying
{B}: Fetid Imp gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Charcoal Diamond

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

Skullclamp

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

Cavern of Souls

As Cavern of Souls enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Archetype of Finality

Creatures you control have deathtouch.
Creatures your opponents control lose deathtouch and can't have or gain deathtouch.

Rat Colony

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

Dark Ritual

Patriar's Seal

{T}: Add one mana of any color.
{1}, {T}: Untap target legendary creature you control.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

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.

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.

Go for the Throat

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.

Mutilate

All creatures get -1/-1 until end of turn for each Swamp you control.

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your first main phase, add {B} for each charge counter on Black Market.

Arcane Signet

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

Sol Ring

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.

Cabal Coffers

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

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Dolmen Gate

Prevent all combat damage that would be dealt to attacking creatures you control.

Vampiric Tutor

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

Damnation

Destroy all creatures. They can't be regenerated.

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.)

Murder

Gnat Miser

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

Cast Down

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.)

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 of their choice.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature of their choice.

Ogre Slumlord

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

Executioner's Capsule

{1}{B}, {T}, Sacrifice Executioner's Capsule: Destroy target nonblack creature.

Drainpipe Vermin

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

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.)

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.