Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

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

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.

Creatures you control gain trample until end of turn. (Each of those creature can deal excess combat damage to the player or planeswalker it's attacking.) Draw a card.

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 token: Add one mana of any color.")

As an additional cost to cast this spell, sacrifice an artifact or discard a card. Draw two cards.

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.

You draw two cards and you lose 2 life.

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

Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

As an additional cost to cast this spell, sacrifice an artifact or creature. You gain life equal to the sacrificed permanent's mana value. Draw two cards.

{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.)

Target player draws two cards and loses 2 life.

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

Spells you cast have ripple 4. (Whenever you cast a spell, you may reveal the top four cards of your library. You may cast spells with the same name as that spell from among the revealed cards without paying their mana costs. Put the rest on the bottom of your library.)

As this artifact enters, 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.

({T}: Add {B} or {R}.) As this land enters, you may pay 2 life. If you don't, it enters tapped.

As this land 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.

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

This land enters tapped unless you control a Swamp or a Mountain. {T}: Add {B} or {R}.

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

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

This land enters tapped unless you control two or more other lands. {T}: Add {B} or {R}.

This land enters tapped. When this land enters, you may put target creature card from your graveyard on top of your library. {T}: Add {B}.

({T}: Add {R}.)

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

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

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

({T}: Add {B} or {R}.) This land enters 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 this turn, instead tap it, remove it from combat, and heal all damage on it.)

{T}: Add {C}. {T}: Add {B} or {R}. Activate only if you control a Swamp.

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.

This land enters tapped. As it enters, choose a color other than black. {T}: Add {B} or one mana of the chosen color.

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

Black creature spells you cast cost {1} less to cast. Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Add {B}{B}{B}.

As this artifact enters, choose a creature type. Creature spells you cast of the chosen type cost {1} less to cast. At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

As this artifact enters, choose a color. Creatures you control of the chosen color get +1/+0. {T}: Add one mana of the chosen color.

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

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.

Creatures you control get +2/+0 until end of turn. Whenever a nontoken creature you control dies this turn, create a 1/1 black Rat creature token with "This token can't block."

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 this creature enters or attacks, create two 1/1 black Rat creature tokens with "This token 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.

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.

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

This token can't block.