Exquisite Blood

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

Dina, Soul Steeper

Whenever you gain life, each opponent loses 1 life.
{1}, Sacrifice another creature: Dina, Soul Steeper gets +X/+0 until end of turn, where X is the sacrificed creature's power.

Chain of Smog

Target player discards two cards. That player may copy this spell and may choose a new target for that copy.

Witherbloom Pledgemage

Magecraft — Whenever you cast or copy an instant or sorcery spell, you gain 1 life.

Sanguine Bond

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

Witherbloom Apprentice

Magecraft — Whenever you cast or copy an instant or sorcery spell, each opponent loses 1 life and you gain 1 life.