Feast of Blood

Cast this spell only if you control two or more Vampires.
Destroy target creature. You gain 4 life.

Swamp

Sangromancer

Flying
Whenever a creature an opponent controls dies, you may gain 3 life.
Whenever an opponent discards a card, you may gain 3 life.

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Master of Dark Rites

{T}, Sacrifice another creature: Add {B}{B}{B}. Spend this mana only to cast Vampire, Cleric, and/or Demon spells.

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.)

Vampire Hexmage

First strike
Sacrifice Vampire Hexmage: Remove all counters from target permanent.

Dark Ritual

Sol Ring

Vampire Nocturnus

Play with the top card of your library revealed.
As long as the top card of your library is black, Vampire Nocturnus and other Vampire creatures you control get +2/+1 and have flying.

Anowon, the Ruin Sage

At the beginning of your upkeep, each player sacrifices a non-Vampire creature of their choice.

Crossway Troublemakers

Attacking Vampires you control have deathtouch and lifelink. (Any amount of damage they deal to a creature is enough to destroy it. Damage dealt by those creatures also causes their controller to gain that much life.)
Whenever a Vampire you control dies, you may pay 2 life. If you do, draw a card.

Cordial Vampire

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

Liliana Vess

+1: Target player discards a card.
−2: Search your library for a card, then shuffle and put that card on top.
−8: Put all creature cards from all graveyards onto the battlefield under your control.

Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature of their choice.

Lord of Lineage

Flying
Other Vampire creatures you control get +2/+2.
{T}: Create a 2/2 black Vampire creature token with flying.

Bloodline Keeper

Flying
{T}: Create a 2/2 black Vampire creature token with flying.
{B}: Transform Bloodline Keeper. Activate only if you control five or more Vampires.