Tainted Remedy

If an opponent would gain life, that player loses that much life instead.

Cloudshift

Exile target creature you control, then return that card to the battlefield under your control.

Wall of Blood

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

Mister Negative

Vigilance, lifelink
Darkforce Inversion — When Mister Negative enters, you may exchange life totals with target opponent. If you lost life this way, draw that many cards.

Hex Parasite

{X}{B/P}: Remove up to X counters from target permanent. For each counter removed this way, this creature gets +1/+0 until end of turn. ({B/P} can be paid with either {B} or 2 life.)

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)