Bloodghast

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

Elenda, the Dusk Rose

Lifelink
Whenever another creature dies, put a +1/+1 counter on Elenda, the Dusk Rose.
When Elenda dies, create X 1/1 white Vampire creature tokens with lifelink, where X is Elenda's power.

Olivia's Wrath

Each non-Vampire creature gets -X/-X until end of turn, where X is the number of Vampires you control.

Mavren Fein, Dusk Apostle

Whenever one or more nontoken Vampires you control attack, create a 1/1 white Vampire creature token with lifelink.

Legion Lieutenant

Welcoming Vampire

Flying
Whenever one or more other creatures with power 2 or less enter the battlefield under your control, draw a card. This ability triggers only once each turn.

Cordial Vampire

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

Bartolomé del Presidio

Sacrifice another creature or artifact: Put a +1/+1 counter on Bartolomé del Presidio.

Master of Dark Rites

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

Clavileño, First of the Blessed

Whenever you attack, target attacking Vampire that isn't a Demon becomes a Demon in addition to its other types. It gains "When this creature dies, draw a card and create a tapped 4/3 white and black Vampire Demon creature token with flying."