Sanguine Bond

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

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Exquisite Blood

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

Sign in Blood

Target player draws two cards and loses 2 life.

Swamp

Sol Ring

Varragoth, Bloodsky Sire

Deathtouch
Boast — {1}{B}: Target player searches their library for a card, then shuffles and puts that card on top. (Activate only if this creature attacked this turn and only once each turn.)