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

Sacrifice a creature: Add {C}{C}.

As this artifact enters, choose a creature type. This artifact enters with a fellowship counter on it for each creature you control of the chosen type. Creatures you control of the chosen type get +1/+1 for each fellowship counter on this artifact.

As this artifact enters, choose a creature type. Whenever you cast a spell of the chosen type, put a charge counter on this artifact. Creatures you control of the chosen type get +1/+1 for each charge counter on this artifact.

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.) Equip {0}

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

{T}: Add one mana of any color. {1}, {T}: Untap target legendary creature you control.

{T}: Add {C}{C}.

Equipped creature gets +1/+1 and has haste. At the beginning of each combat, untap equipped creature. Equipped creature has first strike as long as it's blocking or blocked by a Goblin or Orc. Equip {2}

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.)

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.)

Search your library for a card, put that card into your hand, then shuffle.

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

Whenever Ashcoat 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.)

Defender {T}: Creatures you control gain haste until end of turn.

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.

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.

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

This land enters tapped. When this land enters, exile target player's graveyard. {T}: Add {B}.

{2}, {T}: Add {B} for each Swamp you control.

({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.)

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