Boneyard Scourge

Flying
Whenever a Dragon you control dies while Boneyard Scourge is in your graveyard, you may pay {1}{B}. If you do, return Boneyard Scourge from your graveyard to the battlefield.

Swamp

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.)

Bladewing's Thrall

Bladewing's Thrall has flying as long as you control a Dragon.
When a Dragon enters, you may return Bladewing's Thrall from your graveyard to the battlefield.

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Gravecrawler

Gravecrawler can't block.
You may cast Gravecrawler from your graveyard as long as you control a Zombie.

Dark Ritual

Scourge of Nel Toth

Flying
You may cast Scourge of Nel Toth from your graveyard by paying {B}{B} and sacrificing two creatures rather than paying its mana cost.

Putrid Imp

Discard a card: Putrid Imp gains flying until end of turn.
Threshold — As long as seven or more cards are in your graveyard, Putrid Imp gets +1/+1 and can't block.

Duress

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

Inquisition of Kozilek

Target player reveals their hand. You choose a nonland card from it with mana value 3 or less. That player discards that card.

Hymn to Tourach

Target player discards two cards at random.