Thornplate Intimidator

Offspring {3} (You may pay an additional {3} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
When this creature enters, target opponent loses 3 life unless they sacrifice a nonland permanent of their choice or discard a card.

Rancid Rats

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.)

Zodiac Rat

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Crypt Rats

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

Ruin Rat

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

Earsplitting Rats

When this creature enters, each player discards a card.
Discard a card: Regenerate this creature.

Razortooth Rats

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

Carrion Rats

Whenever this creature attacks or blocks, any player may exile a card from their graveyard. If a player does, this creature assigns no combat damage this turn.

Gutter Skulk

Drainpipe Vermin

When this creature dies, you may pay {B}. If you do, target player discards a card.

Rat Colony

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

Nezumi Cutthroat

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

Mukotai Ambusher

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Lifelink

Muck Rats

Innocuous Rat

When this creature dies, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Thriving Rats

When this creature enters, you get {E}{E} (two energy counters).
Whenever this creature attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it.

Sinuous Vermin

{3}{B}{B}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
As long as this creature is monstrous, it has menace. (It can't be blocked except by two or more creatures.)

Plague Rats

Plague Rats's power and toughness are each equal to the number of creatures named Plague Rats on the battlefield.

Swarm of Rats

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

Blightbelly Rat

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When this creature dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Okiba-Gang Shinobi

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, that player discards two cards.

Kuro's Taken

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

Ossuary Rats

When this creature enters, it deals X damage to target creature or planeswalker an opponent controls, where X is the number of creature cards in your graveyard.

Graf Rats

At the beginning of combat on your turn, if you both own and control this creature and a creature named Midnight Scavengers, exile them, then meld them into Chittering Host.

Ravenous Rats

When this creature enters, target opponent discards a card.

Relentless Rats

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

Daggerfang Duo

Deathtouch
When this creature enters, you may mill two cards. (You may put the top two cards of your library into your graveyard.)

Rats of Rath

{B}: Destroy target artifact, creature, or land you control.

Refurbished Familiar

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When this creature enters, each opponent discards a card. For each opponent who can't, you draw a card.

Midnight Scavengers

When this creature enters, you may return target creature card with mana value 3 or less from your graveyard to your hand.
(Melds with Graf Rats.)

Nezumi Informant

When this creature enters, each opponent discards a card.

Burglar Rat

Sewer Rats

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

Rabid Rats

{T}: Target blocking creature gets -1/-1 until end of turn.

Disease Carriers

When this creature dies, target creature gets -2/-2 until end of turn.

Swamp

Engine Rat

Deathtouch
{5}{B}: Each opponent loses 2 life.

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.)

Nezumi Bladeblesser

This creature has deathtouch as long as you control an artifact.
This creature has menace as long as you control an enchantment. (It can't be blocked except by two or more creatures.)

Deathmask Nezumi

As long as you have seven or more cards in hand, this creature gets +2/+1 and has fear. (It can't be blocked except by artifact creatures and/or black creatures.)

Nezumi Ronin

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

Nezumi Linkbreaker

When this creature dies, create a 1/1 red Mercenary creature token with "{T}: Target creature you control gets +1/+0 until end of turn. Activate only as a sorcery."

Voracious Vermin

When this creature enters, create a 1/1 black Rat creature token with "This token can't block."
Whenever another creature you control dies, put a +1/+1 counter on this creature.

Rotting Rats

When this creature enters, each player discards a card.
Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Chittering Rats

When this creature enters, target opponent puts a card from their hand on top of their library.

Gnat Miser

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

Undercity Dire Rat

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

Dirty Wererat

{B}, Discard a card: Regenerate this creature.
Threshold — As long as seven or more cards are in your graveyard, this creature gets +2/+2 and can't block.

Bog Rats

Typhoid Rats

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