Dark Ritual

Ravenous Rats

When Ravenous Rats enters, target opponent discards a card.

Tortured Existence

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

Carrion Rats

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

Omen of the Dead

Flash
When Omen of the Dead enters, return target creature card from your graveyard to your hand.
{2}{B}, Sacrifice Omen of the Dead: Scry 2.

Swamp

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Raven's Crime

Target player discards a card.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Disentomb

Return target creature card from your graveyard to your hand.

Burglar Rat

When this creature enters, each opponent discards a card.

Drainpipe Vermin

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

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Rotting Rats

When Rotting Rats 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.)

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 Informant

When Nezumi Informant enters, each opponent discards a card.

Gurmag Angler

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)