Vampire Socialite

Menace (This creature can't be blocked except by two or more creatures.)
When Vampire Socialite enters the battlefield, if an opponent lost life this turn, put a +1/+1 counter on each other Vampire you control.
As long as an opponent lost life this turn, each other Vampire you control enters the battlefield with an additional +1/+1 counter on it.

Edgar Markov

Eminence — Whenever you cast another Vampire spell, if Edgar Markov is in the command zone or on the battlefield, create a 1/1 black Vampire creature token.
First strike, haste
Whenever Edgar Markov attacks, put a +1/+1 counter on each Vampire you control.

Ashenmoor Liege

Other black creatures you control get +1/+1.
Other red creatures you control get +1/+1.
Whenever Ashenmoor Liege becomes the target of a spell or ability an opponent controls, that player loses 4 life.

Zagras, Thief of Heartbeats

This spell costs {1} less to cast for each creature in your party.
Flying, deathtouch, haste
Other creatures you control have deathtouch.
Whenever a creature you control deals combat damage to a planeswalker, destroy that planeswalker.

Teysa Karlov

If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Creature tokens you control have vigilance and lifelink.

Markov Purifier

Lifelink
At the beginning of your end step, if you gained life this turn, you may pay {2}. If you do, draw a card.

Strefan, Maurer Progenitor

Flying
At the beginning of your end step, create a Blood token for each player who lost life this turn.
Whenever Strefan attacks, you may sacrifice two Blood tokens. If you do, you may put a Vampire card from your hand onto the battlefield tapped and attacking. It gains indestructible until end of turn.