Tainted Field

{T}: Add {C}.
{T}: Add {W} or {B}. Activate only if you control a Swamp.

Swamp

Stitch Together

Return target creature card from your graveyard to your hand.
Threshold — Return that card from your graveyard to the battlefield instead if seven or more cards are in your graveyard.

Plains

Buried Alive

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

Mindslicer

When Mindslicer dies, each player discards their hand.

Confessor

Whenever a player discards a card, you may gain 1 life.

Mind Burst

Target player discards X cards, where X is one plus the number of cards named Mind Burst in all graveyards.

Skull Fracture

Target player discards a card.
Flashback {3}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Zombie Infestation

Discard two cards: Create a 2/2 black Zombie creature token.

Sickening Dreams

As an additional cost to cast this spell, discard X cards.
Sickening Dreams deals X damage to each creature and each player.

Cabal Shrine

Whenever a player casts a spell, that player discards X cards, where X is the number of cards in all graveyards with the same name as that spell.

Silver Seraph

Flying
Threshold — Other creatures you control get +2/+2 as long as seven or more cards are in your graveyard.

Toxic Stench

Target nonblack creature gets -1/-1 until end of turn.
Threshold — If seven or more cards are in your graveyard, instead destroy that creature. It can't be regenerated.

Spirit Cairn

Whenever a player discards a card, you may pay {W}. If you do, create a 1/1 white Spirit creature token with flying.