Blood Fountain

When this artifact enters, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")
{3}{B}, {T}, Sacrifice this artifact: Return up to two target creature cards from your graveyard to your hand.

Swamp

Crypt Rats

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

Unscrupulous Agent

When this creature enters, target opponent exiles a card from their hand.

Corrupted Conviction

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Hopeless Nightmare

When this enchantment enters, each opponent discards a card and loses 2 life.
When this enchantment is put into a graveyard from the battlefield, scry 2.
{2}{B}: Sacrifice this enchantment.

Defile

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

Toxin Analysis

Target creature gains deathtouch and lifelink until end of turn. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

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.

Troll of Khazad-dûm

This creature can't be blocked except by three or more creatures.
Swampcycling {1} ({1}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Vault of Whispers

Last Rites

Discard any number of cards. Target player reveals their hand, then you choose a nonland card from it for each card discarded this way. That player discards those cards.

Village Rites

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.