Costly Plunder

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards.

Vicious Conquistador

Whenever Vicious Conquistador attacks, each opponent loses 1 life.

Sorin, Imperious Bloodlord

+1: Target creature you control gains deathtouch and lifelink until end of turn. If it's a Vampire, put a +1/+1 counter on it.
+1: You may sacrifice a Vampire. When you do, Sorin, Imperious Bloodlord deals 3 damage to any target and you gain 3 life.
−3: You may put a Vampire creature card from your hand onto the battlefield.

Ob Nixilis's Cruelty

Target creature gets -5/-5 until end of turn. If that creature would die this turn, exile it instead.

Sanctum Seeker

Whenever a Vampire you control attacks, each opponent loses 1 life and you gain 1 life.

Dusk Legion Zealot

When Dusk Legion Zealot enters, you draw a card and you lose 1 life.

Vampire of the Dire Moon

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.)

Knight of the Ebon Legion

{2}{B}: Knight of the Ebon Legion gets +3/+3 and gains deathtouch until end of turn.
At the beginning of your end step, if a player lost 4 or more life this turn, put a +1/+1 counter on Knight of the Ebon Legion. (Damage causes loss of life.)

Blood Operative

Lifelink
When Blood Operative enters, you may exile target card from a graveyard.
Whenever you surveil, if Blood Operative is in your graveyard, you may pay 3 life. If you do, return Blood Operative to your hand.

Swamp

Champion of Dusk

When Champion of Dusk enters, you draw X cards and you lose X life, where X is the number of Vampires you control.