Mischievous Poltergeist

Flying
Pay 1 life: Regenerate Mischievous Poltergeist.

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.

Wall of Blood

Defender (This creature can't attack.)
Pay 1 life: Wall of Blood gets +1/+1 until end of turn.

Ethereal Champion

Pay 1 life: Prevent the next 1 damage that would be dealt to Ethereal Champion this turn.

Cutthroat Contender

Pay 1 life: Cutthroat Contender gets +1/+0 until end of turn. Activate only once each turn.

Carrion Howler

Pay 1 life: Carrion Howler gets +2/-1 until end of turn.

Kozilek's Translator

Devoid (This card has no color.)
Pay 1 life: Add {C}. Activate only once each turn. ({C} represents colorless mana.)