Ruin Rat

Deathtouch
When this creature dies, exile target card from an opponent's graveyard.

Ayara, First of Locthwain

Whenever Ayara or another black creature you control enters, each opponent loses 1 life and you gain 1 life.
{T}, Sacrifice another black creature: Draw a card.

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.)

Stronghold Rats

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever this creature deals combat damage to a player, each player discards a card.

Piper of the Swarm

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.

Skullclamp

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

Species Specialist

As this creature enters, choose a creature type.
Whenever a creature of the chosen type dies, you may draw a card.

Chittering Witch

When this creature enters, create a number of 1/1 black Rat creature tokens equal to the number of opponents you have.
{1}{B}, Sacrifice a creature: Target creature gets -2/-2 until end of turn.

Gnat Miser

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

Swarm of Rats

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

Infernal Grasp

Destroy target creature. You lose 2 life.

Septic Rats

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever this creature attacks, if defending player is poisoned, it gets +1/+1 until end of turn.

Locust Miser

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

Village Rites

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

Burglar Rat

When this creature enters, each opponent discards a card.

Dark Ritual

Ogre Slumlord

Whenever another nontoken creature dies, you may create a 1/1 black Rat creature token.
Rats you control have deathtouch.

Bontu's Monument

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.

Thornbite Staff

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, you may attach this Equipment to it.
Equip {4}

Nezumi Ronin

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

Ichor Rats

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

Marrow-Gnawer

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.

Zulaport Cutthroat

Whenever this creature or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Blood Artist

Whenever this creature or another creature dies, target player loses 1 life and you gain 1 life.

Typhoid Rats

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

Ratcatcher

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.