Oathsworn Vampire

Oathsworn Vampire enters tapped.
You may cast Oathsworn Vampire from your graveyard if you gained life this turn.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Bloodghast

Bloodghast can't block.
Bloodghast has haste as long as an opponent has 10 or less life.
Landfall — Whenever a land you control enters, you may return Bloodghast from your graveyard to the battlefield.

Vampire Nighthawk

Flying
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Cordial Vampire

Whenever Cordial Vampire or another creature dies, put a +1/+1 counter on each Vampire you control.

Gifted Aetherborn

Malakir Bloodwitch

Flying, protection from white
When Malakir Bloodwitch enters, each opponent loses life equal to the number of Vampires you control. You gain life equal to the life lost this way.

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Swamp

Kalastria Highborn

Whenever this creature or another Vampire you control dies, you may pay {B}. If you do, target player loses 2 life and you gain 2 life.

Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.