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.)

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.)

Whenever another Rat enters the battlefield under your control, 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 creature can't block."

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.

You draw two cards and you lose 2 life. Each opponent gets a poison counter.

As Species Specialist enters the battlefield, 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 Cover of Darkness enters the battlefield, choose a creature type. Creatures of the chosen type have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

Enchant creature Enchanted creature has infect. At the beginning of your upkeep, put a -1/-1 counter on enchanted creature. When Glistening Oil is put into a graveyard from the battlefield, return Glistening Oil to its owner's hand.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) When Ichor Rats enters the battlefield, each player gets a poison counter.

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

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

{T}: Add {C}. {4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Path of Ancestry enters the battlefield 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.)

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

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({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.)

When Contagion Clasp enters the battlefield, put a -1/-1 counter on target creature. {4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

When Contagion Engine enters the battlefield, put a -1/-1 counter on each creature target player controls. {4}, {T}: Proliferate, then proliferate again. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Equipped creature gets +2/+2 and has protection from white and from blue. Whenever equipped creature deals combat damage to a player, put a +1/+1 counter on a creature you control, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.) Equip {2}

Compleated ({B/P} can be paid with {B} or 2 life. If life was paid, this planeswalker enters with two fewer loyalty counters.) 0: You draw a card and you lose 1 life. Proliferate. −2: Target creature becomes a Treasure artifact with "{T}, Sacrifice this artifact: Add one mana of any color" and loses all other card types and abilities. −9: If target player has fewer than nine poison counters, they get a number of poison counters equal to the difference.

Creatures you control have flying, first strike, vigilance, trample, haste, and protection from black and from red.

Prevent all combat damage that would be dealt to attacking creatures you control.

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.)

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.) Equip {1}

{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.

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.) Whenever you tap a Swamp for mana, add an additional {B}.

Add {B}{B}{B}.

Glistening Sphere enters the battlefield tapped. When Glistening Sphere enters the battlefield, proliferate. {T}: Add one mana of any color. Corrupted — {T}: Add three mana of any one color. Activate only if an opponent has three or more poison counters.

As Herald's Horn enters the battlefield, 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.

+1: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle. −3: Target creature gets +X/+X or -X/-X until end of turn, where X is the number of Swamps you control. −6: You get an emblem with "Swamps you control have '{T}: Add {B}{B}{B}{B}.'"

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

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.) Whenever a Human deals damage to you, destroy it. Other non-Human creatures you control get +1/+1 and have undying. (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.)

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

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

If you control a commander, you may cast this spell without paying its mana cost. Exile target creature.

Target creature gets -4/-4 until end of turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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

Each opponent gets a poison counter. Then each creature your opponents control gets -1/-1 until end of turn for each poison counter its controller has.

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.) Until end of turn, creatures target player controls lose all abilities and have base power and toughness 0/2.

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.

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.

Black creatures get +1/+1.

You may pay {1}{B} rather than pay this spell's mana cost. If the {1}{B} cost was paid, an opponent draws a card. Exile target creature or planeswalker.

You may look at the top card of your library any time. You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost. {T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

As Caged Sun enters the battlefield, choose a color. Creatures you control of the chosen color get +1/+1. Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Whenever a creature enters the battlefield, you lose 1 life and add {B}.

Changeling (This card is every creature type.) Changeling Outcast can't block and can't be blocked.

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.")

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

Equipped creature gets +2/+2 and has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) Whenever Grafted Exoskeleton becomes unattached from a permanent, sacrifice that permanent. Equip {2}

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

Put a -1/-1 counter on target creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Choose a creature type. Return up to two creature cards of that type from your graveyard to the battlefield. If this spell was foretold, return all creature cards of that type from your graveyard to the battlefield instead. Foretell {5}{B}{B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Destroy all creatures you don't control and all planeswalkers you don't control.

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

Each player exiles all creature cards from their graveyard, then sacrifices all creatures they control, then puts all cards they exiled this way onto the battlefield.

{1}, {T}: Untap another target artifact. {3}, {T}: Target creature can't be blocked this turn.

Menace Creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.) Whenever a creature an opponent controls dies, if its toughness was less than 1, draw a card.

Enchant creature you control Enchanted creature has toxic 2. (Players dealt combat damage by it also get two poison counters.) When enchanted creature dies, return that card to the battlefield under your 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.)

Nyx Lotus enters the battlefield 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.)

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.

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 Pack Rat.

Rat Colony 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.

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

Exile target nonland card from your graveyard. Search your library for any number of cards with the same name as that card, reveal them, put them into your hand, then shuffle.

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

When The Meathook Massacre enters the battlefield, each creature gets -X/-X until end of turn. Whenever a creature you control dies, each opponent loses 1 life. Whenever a creature an opponent controls dies, you gain 1 life.

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

You may have Vesuva enter the battlefield tapped as a copy of any land on the battlefield.