Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Vona, Butcher of Magan

Vigilance, lifelink
{T}, Pay 7 life: Destroy target nonland permanent. Activate only during your turn.

Whenever an opponent loses life, you gain that much life.

{T}, Sacrifice Magus of the Mirror: Exchange life totals with target opponent. Activate only during your upkeep.

At the beginning of your upkeep, you may have two target players exchange life totals.

Flying
{B}, Pay 2 life: Target creature gets -1/-1 until end of turn.
Whenever you lose life, draw that many cards. (Damage causes loss of life.)

{T}, Sacrifice Mirror Universe: Exchange life totals with target opponent. Activate only during your upkeep.