Counterspell

Calamity of Cinders

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.)
Calamity of Cinders deals 6 damage to each untapped creature.

Rakdos Signet

Vren, the Relentless

Ward {2}
If a creature an opponent controls would die, exile it instead.
At the beginning of each end step, create X 1/1 black Rat creature tokens with "This creature gets +1/+1 for each other Rat you control," where X is the number of creatures that were exiled under your opponents' control this turn.

Village Rites

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

Junk Jet

When Junk Jet enters, create a Junk token. (It's an artifact with "{T}, Sacrifice this artifact: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")
{3}, Sacrifice another artifact: Double equipped creature's power until end of turn.
Equip {1}

Splash Portal

Exile target creature you control, then return it to the battlefield under its owner's control. If that creature is a Bird, Frog, Otter, or Rat, draw a card.

Swamp

Mad Ratter

Whenever you draw your second card each turn, create two 1/1 black Rat creature tokens.

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.

Unleash Fury

Double the power of target creature until end of turn.

Psychosis Crawler

Psychosis Crawler's power and toughness are each equal to the number of cards in your hand.
Whenever you draw a card, each opponent loses 1 life.

Exotic Orchard

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

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.)

Patchwork Banner

As Patchwork Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

Fellwar Stone

Dimir Signet

Ogre Slumlord

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

Distant Melody

Choose a creature type. Draw a card for each permanent you control of that type.

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.

Transmogrant's Crown

Equipped creature gets +2/+0.
Whenever equipped creature dies, draw a card.
Equip {2} or {B}

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. Talisman of Dominance deals 1 damage to you.

Blur

Exile target creature you control, then return that card to the battlefield under its owner's control.
Draw a card.

Izzet Signet

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Victimize

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

Skullclamp

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

Mountain

Command Tower

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

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Fountainport

{T}: Add {C}.
{2}, {T}, Sacrifice a token: Draw a card.
{3}, {T}, Pay 1 life: Create a 1/1 blue Fish creature token.
{4}, {T}: Create a Treasure token.

Feed the Swarm

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

Demonmail Hauberk

Equipped creature gets +4/+2.
Equip—Sacrifice a creature.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

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.

Essence Flux

Exile target creature you control, then return that card to the battlefield under its owner's control. If it's a Spirit, put a +1/+1 counter on it.

Sword of the Squeak

Equipped creature gets +1/+1 for each creature you control with base power or toughness 1.
Whenever a Hamster, Mouse, Rat, or Squirrel you control enters, you may attach Sword of the Squeak to that creature.
Equip {2}

Seething Landscape

{T}: Add {C}.
{T}, Sacrifice Seething Landscape: Search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.
Cycling {U}{B}{R} ({U}{B}{R}, Discard this card: Draw a card.)

Grafted Wargear

Equipped creature gets +3/+2.
Whenever Grafted Wargear becomes unattached from a permanent, sacrifice that permanent.
Equip {0} ({0}: Attach to target creature you control. Equip only as a sorcery.)

Arcane Signet

Displacer Kitten

Avoidance — Whenever you cast a noncreature spell, exile up to one target nonland permanent you control, then return that card to the battlefield under its owner's control.

Redcap Gutter-Dweller

Menace
When this creature enters, create two 1/1 black Rat creature tokens with "This token can't block."
At the beginning of your upkeep, you may sacrifice another creature. If you do, put a +1/+1 counter on this creature and exile the top card of your library. You may play that card this turn.

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Wick, the Whorled Mind

Whenever Wick or another Rat you control enters, create a 1/1 black Snail creature token if you don't control a Snail. Otherwise, put a +1/+1 counter on a Snail you control.
{U}{B}{R}, Sacrifice a Snail: Wick deals damage equal to the sacrificed creature's power to each opponent. Then draw cards equal to the sacrificed creature's power.

Sol Ring

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.

Long River Lurker

Ward {1}
Other Frogs you control have ward {1}.
When Long River Lurker enters, target creature you control can't be blocked this turn. Whenever that creature deals combat damage this turn, you may exile it. If you do, return it to the battlefield under its owner's control.

Terminate

Destroy target creature. It can't be regenerated.

Basilisk Collar

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

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."

Negate

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.

Rush of Blood

Target creature gets +X/+0 until end of turn, where X is its power.

Ogre Chitterlord

Menace
Whenever Ogre Chitterlord enters or attacks, create two 1/1 black Rat creature tokens with "This creature can't block." Then if you control five or more Rats, each Rat you control gets +2/+0 until end of turn.

Lich-Knights' Conquest

Sacrifice any number of artifacts, enchantments, and/or tokens. Return that many creature cards from your graveyard to the battlefield.

Molten Gatekeeper

Whenever another creature you control enters, Molten Gatekeeper deals 1 damage to each opponent.
Unearth {R} ({R}: 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.)

Thought Vessel

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

City on Fire

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.)
If a source you control would deal damage to a permanent or player, it deals triple that damage instead.

Island

Mirkwood Bats

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

Reliquary Tower

Totentanz, Swarm Piper

Whenever Totentanz, Swarm Piper or another nontoken creature you control dies, create a 1/1 black Rat creature token with "This creature can't block."
{1}{B}: Target attacking Rat you control gains deathtouch until end of turn.

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Phyresis

Enchant creature
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

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.

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

Twisted Sewer-Witch

When Twisted Sewer-Witch 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 Aura is put into a graveyard, each opponent loses 1 life.)

Tainted Strike

Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Mudflat Village

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

Planar Incision

Exile target artifact or creature, then return it to the battlefield under its owner's control with a +1/+1 counter on it.

Fatal Frenzy

Until end of turn, target creature you control gains trample and gets +X/+0, where X is its power. Sacrifice it at the beginning of the next end step.

Song of Totentanz

Create X 1/1 black Rat creature tokens with "This creature can't block." Creatures you control gain haste until end of turn.