Bog Rats can't be blocked by Walls.

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

, : Each creature with mana value X can't attack or block this turn.

Hellbent — As long as you have no cards in hand, Gobhobbler Rats gets +1/+0 and has ": Regenerate Gobhobbler Rats." (The next time it would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Haste

When Hellhole Rats enters, target player discards a card. Hellhole Rats deals damage to that player equal to that card's mana value.

Buyback (You may pay an additional 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.

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

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

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.)

: Destroy target artifact, creature, or land you control.

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

Create a tapped 1/1 black Rat creature token for each creature card in your graveyard.

Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

Shadow (This creature can block or be blocked by only creatures with shadow.)

Whenever Stronghold Rats deals combat damage to a player, each player discards a card.

When Thriving Rats enters, you get (two energy counters).

Whenever Thriving Rats attacks, you may pay . If you do, put a +1/+1 counter on it.

Trample

When Wave of Rats dies, if it dealt combat damage to a player this turn, return it to the battlefield under its owner's control.

Blitz (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)