Lord of the Forsaken

Flying, trample
{B}, Sacrifice another creature: Target player mills three cards.
Pay 1 life: Add {C}. Spend this mana only to cast a spell from your graveyard.

Cavern Harpy

Flying
When this creature enters, return a blue or black creature you control to its owner's hand.
Pay 1 life: Return this creature to its owner's hand.

Spatial Binding

Pay 1 life: Until your next upkeep, target permanent can't phase out.

Codie, Vociferous Codex

You can't cast permanent spells.
{4}, {T}: Add {W}{U}{B}{R}{G}. When you next cast a spell this turn, exile cards from the top of your library until you exile an instant or sorcery card with lesser mana value. Until end of turn, you may cast that card without paying its mana cost. Put each other card exiled this way on the bottom of your library in a random order.

Blood Celebrant

{B}, Pay 1 life: Add one mana of any color.

Carrion Howler

Pay 1 life: This creature gets +2/-1 until end of turn.

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Mischievous Poltergeist

Flying
Pay 1 life: Regenerate this creature.

Souldrinker

Pay 3 life: Put a +1/+1 counter on this creature.

Martyrs' Tomb

Pay 2 life: Prevent the next 1 damage that would be dealt to target creature this turn.