As Adaptive Automaton enters the battlefield, choose a creature type.

Adaptive Automaton is the chosen type in addition to its other types.

Other creatures you control of the chosen type get +1/+1.

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.

Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

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

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.

Black creatures get +1/+1.

Whenever a creature dies, put a charge counter on Black Market.

At the beginning of your precombat main phase, add {B} for each charge counter on Black Market.

Bojuka Bog enters the battlefield tapped.

When Bojuka Bog enters the battlefield, exile target player's graveyard.

{T}: Add {B}.

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.

When Burglar Rat enters the battlefield, each opponent discards a card.

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

{T}: Add {C}.

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

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.

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.)

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.)

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}.

{X}: Crypt Rats deals X damage to each creature and each player. Spend only black mana on X.

Add {B}{B}{B}.

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

Exile target creature.

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

Flash

Whenever a creature you control dies, each opponent sacrifices a creature.

As Door of Destinies enters the battlefield, choose a creature type.

Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies.

Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.

Creatures you control get +1/+1 and have flying and indestructible.

At the beginning of your upkeep, sacrifice a creature. If you can't, sacrifice Eldrazi Monument.

Indestructible

As long as your devotion to black is less than five, Erebos isn't a creature.

Whenever another creature you control dies, you may pay 2 life. If you do, draw a card.

{1}{B}, Sacrifice another creature: Target creature gets -2/-1 until end of turn.

Whenever an opponent loses life, you gain that much life.

Each opponent loses X life. You gain life equal to the life lost this way.

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

Target opponent loses 1 life for each attacking creature you control. You gain that much life.

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

As Heraldic Banner enters the battlefield, choose a color.

Creatures you control of the chosen color get +1/+0.

{T}: Add one mana of the chosen color.

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.

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

Equip {0}

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.

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

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 Metallic Mimic enters the battlefield, choose a creature type.

Metallic Mimic is the chosen type in addition to its other types.

Each other creature you control of the chosen type enters the battlefield with an additional +1/+1 counter on it.

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.)

{T}: Add {C}.

{1}, {T}, Sacrifice Mind Stone: Draw a card.

You draw two cards and you lose 2 life.

{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.)

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 Pack Rat.

Choose a creature type. Target player draws X cards and loses X life, where X is the number of creatures they control of the chosen type.

At the beginning of the end step, if no creatures are on the battlefield, sacrifice Pestilence.

{B}: Pestilence deals 1 damage to each creature and each player.

Pestilence Rats's power is equal to the number of other Rats on the battlefield. (For example, as long as there are two other Rats on the battlefield, Pestilence Rats's power and toughness are 2/3.)

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.

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.

As an additional cost to cast this spell, you may sacrifice one or more creatures. When you do, copy this spell for each creature sacrificed this way.

You draw a card and you lose 1 life.

Skulk (This creature can't be blocked by creatures with greater power.)

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

Rat Colony gets +1/+0 for each other Rat you control.

A deck can have any number of cards named Rat Colony.

{T}: Add {C}.

{2}, {T}, Sacrifice a Desert: Exile all graveyards.

{T}: Exile the top card of target player's library. If it's a land card, you gain 1 life.

Landfall -- Whenever a land enters the battlefield under your control, you may untap Scrib Nibblers.

{1}: Look at the top three cards of your library, then put them back in any order.

{T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Whenever Septic Rats attacks, if defending player is poisoned, it gets +1/+1 until end of turn.

Target player draws two cards and loses 2 life.

Equipped creature gets +1/-1.

Whenever equipped creature dies, draw two cards.

Equip {1}

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

As Species Specialist enters the battlefield, choose a creature type.

Whenever a creature of the chosen type dies, you may draw a card.

{T}: Add {C}.

{T}, Sacrifice Strip Mine: Destroy target land.

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.

({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 {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

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

{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.)

Equipped creature gets +2/+2 and has protection from green and from white.

Whenever equipped creature deals combat damage to a player, exile up to one target creature you own, then search your library for a basic land card. Put both cards onto the battlefield under your control, then shuffle.

Equip {2}

Equipped creature gets +1/+1.

Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Equip {2}

{T}: Add {C}.

{2}, {T}: Thespian's Stage becomes a copy of target land, except it has this ability.

Equipped creature has "{2}, {T}: This creature deals 1 damage to any target" and "Whenever a creature dies, untap this creature."

Whenever a Shaman creature enters the battlefield, you may attach Thornbite Staff to it.

Equip {4}

As an additional cost to cast this spell, pay X life.

All creatures get -X/-X until end of turn.

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

Each land is a Swamp in addition to its other land types.

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.

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

Whenever you gain life, target opponent loses that much life.

{3}{B}{B}: Creatures you control gain lifelink until end of turn.

Equipped creature gets +2/+0 and has deathtouch.

{5}{B}{B}{B}: Until end of turn, Vorpal Sword gains "Whenever equipped creature deals combat damage to a player, that player loses the game."

Equip {B}{B}