Typhoid Rats

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

Twisted Sewer-Witch

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.)

Not Dead After All

Until end of turn, target creature you control gains "When this creature dies, return it to the battlefield tapped under its owner's control, then create a Wicked Role token attached to it." (Enchanted creature gets +1/+1. When this token is put into a graveyard, each opponent loses 1 life.)

Shiv's Embrace

Enchant creature
Enchanted creature gets +2/+2 and has flying.
{R}: Enchanted creature gets +1/+0 until end of turn.

Mountain

Flick a Coin

Flick a Coin deals 1 damage to any target. You create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Draw a card.

Bone Splinters

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Surgical Extraction

({B/P} can be paid with either {B} or 2 life.)
Choose target card in a graveyard other than a basic land card. Search its owner's graveyard, hand, and library for any number of cards with the same name as that card and exile them. Then that player shuffles.

The End

This spell costs {2} less to cast if your life total is 5 or less.
Exile target creature or planeswalker. Search its controller's graveyard, hand, and library for any number of cards with the same name as that permanent and exile them. That player shuffles, then draws a card for each card exiled from their hand this way.

Raid Bombardment

Whenever a creature you control with power 2 or less attacks, this enchantment deals 1 damage to the player or planeswalker that creature is attacking.

Vampiric Rites

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

Coronation of Chaos

Up to three target creatures can't block this turn. Goad them. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

Bloodstained Mire

{T}, Pay 1 life, Sacrifice this land: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Gnawing Crescendo

Creatures you control get +2/+0 until end of turn. Whenever a nontoken creature you control dies this turn, create a 1/1 black Rat creature token with "This token can't block."

Village Rites

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

Collector's Vault

{2}, {T}: Draw a card, then discard a card. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Animate Dead

Enchant creature card in a graveyard
When this Aura enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with this Aura." Return enchanted creature card to the battlefield under your control and attach this Aura to it. When this Aura leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Tormod's Crypt

{T}, Sacrifice this artifact: Exile target player's graveyard.

Rakdos Guildgate

This land enters tapped.
{T}: Add {B} or {R}.

Rat Out

Up to one target creature gets -1/-1 until end of turn. You create a 1/1 black Rat creature token with "This token can't block."

Pestilence Rats

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.)

Sewer Rats

{B}, Pay 1 life: This creature gets +1/+0 until end of turn. Activate no more than three times each turn.

Thriving Moor

This land enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Lord Skitter's Butcher

When this creature enters, choose one —
• Create a 1/1 black Rat creature token with "This token can't block."
• You may sacrifice another creature. If you do, scry 2, then draw a card.
• Creatures you control gain menace until end of turn.

Redcap Gutter-Dweller

Menace
When this creature enters, create two 1/1 black Rat creature tokens with "This token can't block."
At the beginning of your upkeep, you may sacrifice another creature. If you do, put a +1/+1 counter on this creature and exile the top card of your library. You may play that card this turn.

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.

Totentanz, Swarm Piper

Whenever Totentanz or another nontoken creature you control dies, create a 1/1 black Rat creature token with "This token can't block."
{1}{B}: Target attacking Rat you control gains deathtouch until end of turn.

Hideous Visage

Creatures you control gain intimidate until end of turn. (Each of those creatures can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Tattered Ratter

Whenever a Rat you control becomes blocked, it gets +2/+0 until end of turn.

Ogre Chitterlord

Menace
Whenever this creature enters or attacks, create two 1/1 black Rat creature tokens with "This token can't block." Then if you control five or more Rats, each Rat you control gets +2/+0 until end of turn.

Swamp

Redcap Thief

When this creature enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Bloodfell Caves

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {R}.