Lab Rats

Buyback {4} (You may pay an additional {4} as you cast this spell. If you do, put this card into your hand as it resolves.)
Create a 1/1 black Rat creature token.

Sign in Blood

Target player draws two cards and loses 2 life.

Phyresis

Enchant creature
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Savage Gorger

Flying
At the beginning of your end step, if an opponent lost life this turn, put a +1/+1 counter on Savage Gorger. (Damage causes loss of life.)

Swarm of Rats

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

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Night's Whisper

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Skyshaper

Sacrifice Skyshaper: Creatures you control gain flying until end of turn.

Spirit Shackle

Enchant creature
Whenever enchanted creature becomes tapped, put a -0/-2 counter on it.

Fear

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature has fear. (It can't be blocked except by artifact creatures and/or black creatures.)

Death Denied

Return X target creature cards from your graveyard to your hand.

Witch's Cottage

({T}: Add {B}.)
Witch's Cottage enters tapped unless you control three or more other Swamps.
When Witch's Cottage enters untapped, you may put target creature card from your graveyard on top of your library.

Terror

Destroy target nonartifact, nonblack creature. It can't be regenerated.

Rat Colony

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

Razortooth Rats

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Mind Stone

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

Burglar Rat

When this creature enters, each opponent discards a card.

Recover

Return target creature card from your graveyard to your hand.
Draw a card.

Gravepurge

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

Sisay's Ring

Ravenous Rats

When Ravenous Rats enters, target opponent discards a card.

Thorn of the Black Rose

Deathtouch
When Thorn of the Black Rose enters, you become the monarch.

Swamp

Dark Ritual

Rend Flesh

Ill-Gotten Inheritance

At the beginning of your upkeep, Ill-Gotten Inheritance deals 1 damage to each opponent and you gain 1 life.
{5}{B}, Sacrifice Ill-Gotten Inheritance: It deals 4 damage to target opponent and you gain 4 life.

Pestilence

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.

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Impale

Relentless Rats

Relentless Rats gets +1/+1 for each other creature on the battlefield named Relentless Rats.
A deck can have any number of cards named Relentless Rats.

Gnat Miser

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

Feed the Swarm

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

Seizures

Enchant creature
Whenever enchanted creature becomes tapped, Seizures deals 3 damage to that creature's controller unless that player pays {3}.

Doom Blade

Rush of Vitality

Target creature gets +1/+0 and gains lifelink and indestructible until end of turn. (Damage dealt by that creature also causes its controller to gain that much life, and it can't be destroyed by damage or effects that say "destroy.")

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Macabre Waltz

Return up to two target creature cards from your graveyard to your hand, then discard a card.

Mortuary Mire

Mortuary Mire enters tapped.
When Mortuary Mire enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Arcane Signet

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

Tortured Existence

{B}, Discard a creature card: Return target creature card from your graveyard to your hand.