Psychic Whorl

Target opponent discards two cards. Then if you control a Rat, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Thornplate Intimidator

Offspring {3} (You may pay an additional {3} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
When this creature enters, target opponent loses 3 life unless they sacrifice a nonland permanent of their choice or discard a card.

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 this creature attacks, if defending player is poisoned, it gets +1/+1 until end of turn.

Twisted Sewer-Witch

When this creature enters, 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 token is put into a graveyard, each opponent loses 1 life.)

Valley Rotcaller

Menace
Whenever this creature attacks, each opponent loses X life and you gain X life, where X is the number of other Squirrels, Bats, Lizards, and Rats you control.

Gray Merchant of Asphodel

When this creature enters, 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.)

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.)

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 token can't block."

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 token: You gain 3 life.")
{2}{B}, Sacrifice another creature or artifact: Old Flitterfang gets +2/+2 until end of turn.

Thriving Rats

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

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.

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.)

Refurbished Familiar

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When this creature enters, each opponent discards a card. For each opponent who can't, you draw a card.

Rats' Feast

Exile X target cards from a single graveyard.

Sol Ring

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Coiling Rebirth

Gift a card (You may promise an opponent a gift as you cast this spell. If you do, they draw a card before its other effects.)
Return target creature card from your graveyard to the battlefield. Then if the gift was promised and that creature isn't legendary, create a token that's a copy of that creature, except it's 1/1.

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.)

Voracious Vermin

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

Unseal the Necropolis

Each player mills three cards. Then you return up to two creature cards from your graveyard to your hand. (To mill three cards, a player puts the top three cards of their library into their graveyard.)

Infectious Inquiry

You draw two cards and you lose 2 life. Each opponent gets a poison counter.

Gnat Miser

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

Kindred Dominance

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

Swamp

Sewer Rats

{B}, Pay 1 life: This creature gets +1/+0 until end of turn. Activate no more than three times each turn.

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.

The Dross Pits

This land enters tapped.
{T}: Add {B}.
{1}{B}, {T}, Sacrifice this land: Draw a card.

Changeling Outcast

Changeling (This card is every creature type.)
This creature can't block and can't be blocked.

Reckless Spite

Destroy two target nonblack creatures. You lose 5 life.

Daggerfang Duo

Deathtouch
When this creature enters, you may mill two cards. (You may put the top two cards of your library into your graveyard.)

Arcane Signet

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

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.

Ravenous Rats

When this creature enters, target opponent discards a card.

Lord Skitter's Butcher

When this creature enters, choose one —
• Create a 1/1 black Rat creature token with "This token 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.

Persistent Marshstalker

This creature gets +1/+0 for each other Rat you control.
Threshold — Whenever you attack with one or more Rats, if seven or more cards are in your graveyard, you may pay {2}{B}. If you do, return this card from your graveyard to the battlefield tapped and attacking.

Mudflat Village

{T}: Add {C}.
{T}: Add {B}. Spend this mana only to cast a creature spell.
{1}{B}, {T}, Sacrifice this land: Return target Bat, Lizard, Rat, or Squirrel card from your graveyard to your hand.

Ossuary Rats

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

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Tangled Colony

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

Wick's Patrol

When this creature enters, mill three cards. When you do, target creature an opponent controls gets -X/-X until end of turn, where X is the greatest mana value among cards in your graveyard.

Ruin Rat

Deathtouch
When this creature dies, exile target card from an opponent's graveyard.

Nezumi Informant

When this creature enters, each opponent discards a card.

Crypt Rats

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

Breathe Your Last

Destroy target creature or planeswalker. You gain 1 life for each of its colors.

Rat Out

Up to one target creature gets -1/-1 until end of turn. You create a 1/1 black Rat creature token with "This token can't block."

Ogre Slumlord

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

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 this creature.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Phyrexian Arena

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

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.)

Typhoid Rats

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

Earsplitting Rats

When this creature enters, each player discards a card.
Discard a card: Regenerate this creature.

Vraska's Fall

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

Doom Blade

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.)

Chittering Rats

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

Rabid Rats

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

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.

Razortooth Rats

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

Memorial to Folly

This land enters tapped.
{T}: Add {B}.
{2}{B}, {T}, Sacrifice this land: Return target creature card from your graveyard to your hand.

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 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.

Gnawing Vermin

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

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 this creature enters, target creature you control gains deathtouch and lifelink 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.)

Ayara, First of Locthwain

Whenever Ayara 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.

Blightbelly Rat

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

Nezumi Linkbreaker

When this creature dies, create a 1/1 red Mercenary creature token with "{T}: Target creature you control gets +1/+0 until end of turn. Activate only as a sorcery."

Feed the Swarm

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

Burglar Rat

Lord Skitter's Blessing

When this enchantment enters, create a Wicked Role token attached to target creature you control. (Enchanted creature gets +1/+1. When this token 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.

V.A.T.S.

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Choose any number of target creatures with equal toughness. Destroy the chosen creatures.