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.)

Olivia's Wrath

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

Cordial Vampire

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

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

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.

Stromkirk Captain

First strike
Other Vampire creatures you control get +1/+1 and have first strike.

Veinwitch Coven

Menace
Whenever you gain life, you may pay {B}. If you do, return target creature card from your graveyard to your hand.

Bloodtracker

Flying
{B}, Pay 2 life: Put a +1/+1 counter on Bloodtracker.
When Bloodtracker leaves the battlefield, draw a card for each +1/+1 counter on it.

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.

Patron of the Vein

Flying
When Patron of the Vein enters, destroy target creature an opponent controls.
Whenever a creature an opponent controls dies, exile it and put a +1/+1 counter on each Vampire you control.

Bloodline Necromancer

Lifelink
When Bloodline Necromancer enters, you may return target Vampire or Wizard creature card from your graveyard to the battlefield.