Add {B}{B}{B}.

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.")

Target creature gets -1/-1 until end of turn for each Swamp you control.

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

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.

This artifact enters tapped. {T}: Add {B}.

As this artifact enters, choose a color. Creatures of the chosen color get +1/+1. Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

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.

Black spells you cast cost {1} less to cast.

{T}, Sacrifice this artifact: Add three mana of any one color. Spend this mana only to cast your commander.

At the beginning of your upkeep, flip a coin. If you lose the flip, this artifact deals 3 damage to you. {T}: Add {C}{C}.

Nyx Lotus enters tapped. {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

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

As Throne of Eldraine enters, choose a color. {T}: Add four mana of the chosen color. Spend this mana only to cast monocolored spells of that color. {3}, {T}: Draw two cards. Spend only mana of the chosen color to activate this ability.

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.)

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

{T}: Add {C}. {2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents 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.)

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.)

Each opponent's maximum hand size is reduced by one.

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 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 token can't block."

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

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

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 this creature.

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.

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

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.

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

Shadow (This creature can block or be blocked by only creatures with shadow.) Whenever this creature deals combat damage to a player, each player discards a card.

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

Ninjutsu {2}{B} ({2}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.) Whenever this creature deals combat damage to a player, destroy target nonblack creature that player controls.

When this creature 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 token is put into a graveyard, each opponent loses 1 life.)

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

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

As an additional cost to cast this spell, sacrifice a creature. Search your library for a card, put that card into your hand, then shuffle.

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

Return target creature card and all other cards with the same name as that card from your graveyard to your hand.

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

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

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.

Each opponent loses 1 life for each creature you control.

Each player chooses a creature type. Each player returns all creature cards of a type chosen this way from their graveyard to the battlefield.

Starting with you, each player may pay any amount of life. Repeat this process until no one pays life. Each player creates a 1/1 black Rat creature token for each 1 life they paid this way.

Black creatures get +1/+1.

Whenever a creature dies, put a charge counter on this enchantment. At the beginning of your first main phase, add {B} for each charge counter on this enchantment.

Flash Whenever a creature you control dies, each opponent sacrifices a creature of their choice.

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

{B}, Pay 2 life: Draw a card.

Commander creatures you own have "Whenever this creature becomes tapped, it and other creatures you control that share a creature type with it each get +2/+0 and gain undying until end of turn." (When a creature with undying dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)