Dead Revels

Spectacle {1}{B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Return up to two target creature cards from your graveyard to your hand.

Rabid Rats

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

Cower in Fear

Creatures your opponents control get -1/-1 until end of turn.

Opal Palace

{T}: Add {C}.
{1}, {T}: Add one mana of any color in your commander's color identity. If you spend this mana to cast your commander, it enters the battlefield with a number of additional +1/+1 counters on it equal to the number of times it's been cast from the command zone this game.

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 enters the battlefield under your control, you may untap Scrib Nibblers.

Gnawing Vermin

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

Swamp

Ravenous Rats

When Ravenous Rats enters the battlefield, target opponent discards a card.

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.

Sorin's Thirst

Sorin's Thirst deals 2 damage to target creature and you gain 2 life.

Rat Colony

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

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.

Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Cradle to Grave

Destroy target nonblack creature that entered the battlefield this turn.

Leaden Myr

Necrotic Fumes

As an additional cost to cast this spell, exile a creature you control.
Exile target creature or planeswalker.

Radiant Fountain

When Radiant Fountain enters the battlefield, you gain 2 life.
{T}: Add {C}.

Festergloom

Nonblack creatures get -1/-1 until end of turn.

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.

Mortuary Mire

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

Wail of the Nim

Choose one —
• Regenerate each creature you control.
• Wail of the Nim deals 1 damage to each creature and each player.
Entwine {B} (Choose both if you pay the entwine cost.)

Tanglebloom

Phyrexian Atlas

{T}: Add one mana of any color.
Corrupted — Whenever Phyrexian Atlas becomes tapped, each opponent who has three or more poison counters loses 1 life.

Blood Price

Look at the top four cards of your library. Put two of them into your hand and the rest on the bottom of your library in any order. You lose 2 life.

Swarm of Rats

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

Bitter Revelation

Look at the top four cards of your library. Put two of them into your hand and the rest into your graveyard. You lose 2 life.

Cultist of the Absolute

Commander creatures you own get +3/+3 and have flying, deathtouch, "Ward—Pay 3 life," and "At the beginning of your upkeep, sacrifice a creature."

Parasitic Grasp

Cleave {1}{B}{B} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Parasitic Grasp deals 3 damage to target [Human] creature. You gain 3 life.

Nezumi Informant

When Nezumi Informant enters the battlefield, each opponent discards a card.

Typhoid Rats

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

Victimize

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

Vat Emergence

Put target creature card from a graveyard onto the battlefield under your control. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Ayara, First of Locthwain

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

Cast Down

Bladebrand

Target creature gains deathtouch until end of turn.
Draw a card.

Mirrodin Avenged

Destroy target creature that was dealt damage this turn.
Draw a card.

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.

Cremate

Exile target card from a graveyard.
Draw a card.

Glistening Deluge

All creatures get -1/-1 until end of turn. Creatures that are green and/or white get an additional -2/-2 until end of turn.

Drag to the Bottom

Domain — Each creature gets -X/-X until end of turn, where X is 1 plus the number of basic land types among lands you control.

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.)

Elspeth's Nightmare

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Destroy target creature an opponent controls with power 2 or less.
II — Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.
III — Exile target opponent's graveyard.

Grandmother Ravi Sengir

Flying
Whenever a creature an opponent controls dies, put a +1/+1 counter on Grandmother Ravi Sengir and you gain 1 life.

Invasion of Ulgrotha

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Ulgrotha enters the battlefield, it deals 3 damage to any other target and you gain 3 life.

Invasion of Ulgrotha // Grandmother Ravi Sengir

Vermin Gorger

{T}, Sacrifice another creature: Each opponent loses 2 life and you gain 2 life.

Mage Hunters' Onslaught

Destroy target creature or planeswalker.
Whenever a creature blocks this turn, its controller loses 1 life.

Ichor Shade

At the beginning of your end step, if an artifact or creature was put into a graveyard from the battlefield this turn, put a +1/+1 counter on Ichor Shade.

Scourge of Nel Toth

Flying
You may cast Scourge of Nel Toth from your graveyard by paying {B}{B} and sacrificing two creatures rather than paying its mana cost.

Epicure of Blood

Whenever you gain life, each opponent loses 1 life.

Altar's Reap

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

Cryptic Caves

{T}: Add {C}.
{1}, {T}, Sacrifice Cryptic Caves: Draw a card. Activate only if you control five or more lands.

Ghoulcaller's Chant

Choose one —
• Return target creature card from your graveyard to your hand.
• Return two target Zombie cards from your graveyard to your hand.

Ogre Slumlord

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

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 the battlefield, choose a creature type.
Creatures you control of the chosen type get +2/+2.

Unlikely Aid

Target creature gets +2/+0 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

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.

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.

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 the battlefield, 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.

Gravepurge

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

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

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.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Make Obsolete

Crippling Fear

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

Anoint with Affliction

Exile target creature if it has mana value 3 or less.
Corrupted — Exile that creature instead if its controller has three or more poison counters.

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.

Crypt Rats

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