Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.

Whenever a creature enters the battlefield under your control, Impact Tremors deals 1 damage to each opponent.

Indestructible As long as your devotion to red is less than five, Purphoros isn't a creature. Whenever another creature enters the battlefield under your control, Purphoros deals 2 damage to each opponent. {2}{R}: Creatures you control get +1/+0 until end of turn.

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.)

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

Relentless Rats gets +1/+1 for each other creature on the battlefield named Relentless Rats. A deck can have any number of cards named Relentless Rats.

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

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.

When Twisted Sewer-Witch enters the battlefield, 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.)

When Bastion of Remembrance enters the battlefield, create a 1/1 white Human Soldier creature token. Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

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

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

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.

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

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.")

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.

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.

As an additional cost to cast this spell, you may sacrifice one or more creatures. When you do, copy this spell for each creature sacrificed this way. You draw a card and you lose 1 life.

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

{1}{B}, {T}, Sacrifice another creature: Draw X cards, where X is that creature's power. Choose a Background (You can have a Background as a second commander.)

As Species Specialist enters the battlefield, choose a creature type. Whenever a creature of the chosen type dies, you may draw a card.

As Vanquisher's Banner enters the battlefield, choose a creature type. Creatures you control of the chosen type get +1/+1. Whenever you cast a creature spell of the chosen type, draw a card.

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

Castle Embereth enters the battlefield tapped unless you control a Mountain. {T}: Add {R}. {1}{R}{R}, {T}: Creatures you control get +1/+0 until end of turn.

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

Dragonskull Summit enters the battlefield tapped unless you control a Swamp or a Mountain. {T}: Add {B} or {R}.

As Foreboding Ruins enters the battlefield, you may reveal a Swamp or Mountain card from your hand. If you don't, Foreboding Ruins enters the battlefield tapped. {T}: Add {B} or {R}.

{T}: Add {C}. {B/R}, {T}: Add {B}{B}, {B}{R}, or {R}{R}.

Haunted Ridge enters the battlefield tapped unless you control two or more other lands. {T}: Add {B} or {R}.

Luxury Suite enters the battlefield tapped unless you have two or more opponents. {T}: Add {B} or {R}.

({T}: Add {R}.)

{T}: Add {C}. {T}, Sacrifice a creature: Add {B}{B}.

({T}: Add {B} or {R}.) Smoldering Marsh enters the battlefield tapped unless you control two or more basic lands.

({T}: Add {B}.)

{T}: Add {C}. {T}: Regenerate target Insect, Rat, Spider, or Squirrel. (The next time it would be destroyed, instead tap it, remove it from combat, and heal all damage on it.)

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

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

Whenever one or more creatures you control deal combat damage to a player, create two Treasure tokens. {B}, Sacrifice X Treasures: Target creature gets -X/-X until end of turn. Activate only as a sorcery.

At the beginning of your end step, create a Treasure token for each creature that died this turn. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

{1}, {T}: Add {B}{R}.

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.)

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.

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.

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

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

As an additional cost to cast this spell, sacrifice a creature or pay {3}{B}. Exile target creature or planeswalker.

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

Whenever a creature you control dies, each other player sacrifices a creature.

As an additional cost to cast this spell, sacrifice a creature or pay {4}. Destroy target creature.

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Sacrifice a creature: Goblin Bombardment deals 1 damage to any target.

If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time. {B/P}{B/P}, Exile three creature cards from your graveyard: Put an indestructible counter on Drivnod, Carnage Dominus. ({B/P} can be paid with either {B} or 2 life.)

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.

Menace Whenever Ogre Chitterlord enters the battlefield 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.

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

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.