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.

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

{T}: Add {C}{C}. {2}, {T}, Sacrifice this artifact: Draw two cards.

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 creature type. Creatures you control of the chosen type get +1/+1. {3}, {T}: Look at the top three cards of your library. You may reveal a creature card of the chosen type from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Equipped creature gets +1/-1. Whenever equipped creature dies, draw two cards. Equip {1}

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

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.)

Equipped creature gets +2/+2 and has protection from black and from green. Whenever equipped creature deals combat damage to a player, that player discards a card and you untap all lands you control. Equip {2}

Whenever a creature you control with power equal to its toughness enters, you may pay {1}. If you do, 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.

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.) As long as this card is in your graveyard and you control a Swamp, creatures you control have swampwalk.

Whenever a creature deals combat damage to one of your opponents, its controller may pay 1 life. If they do, they draw a card. {4}{B}{B}{B}, Discard X cards: Exile the top X cards of target opponent's library. You may play lands and cast spells from among cards exiled this way without paying their mana costs.

When this creature enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

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.

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.

As this creature enters, choose a creature type. This creature is the chosen type in addition to its other types. Each other creature you control of the chosen type enters with an additional +1/+1 counter on it.

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.

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.

Flying, trample Pay 2 life, Sacrifice another creature: Search your library for a card, put that card into your hand, then shuffle.

This creature 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.

Trample When this creature dies, if it dealt combat damage to a player this turn, return it to the battlefield under its owner's control. Blitz {4}{B} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

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.)

Creatures you control have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

Skip your draw step. Whenever you discard a card, exile that card from your graveyard. Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

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

Add {B}{B}{B}.

Prevent all combat damage that would be dealt this turn.

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

{T}: Add {C}. {3}, {T}: Add {B} for each basic Swamp you control.

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}.

This land enters tapped. {T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

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

({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.)

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.

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

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Put all creature cards from all graveyards onto the battlefield under your control.