Malicious Invader

Flying
Malicious Invader gets +2/+0 as long as an opponent controls a Human.

Innocent Traveler

At the beginning of your upkeep, any opponent may sacrifice a creature of their choice. If no one does, transform Innocent Traveler.

Innocent Traveler // Malicious Invader

Markov's Servant

Chosen of Markov

{T}, Tap an untapped Vampire you control: Transform Chosen of Markov.

Chosen of Markov // Markov's Servant

Famished Paladin

Famished Paladin doesn't untap during your untap step.
Whenever you gain life, untap Famished Paladin.

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.

Cordial Vampire

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

Arvad the Cursed

Deathtouch, lifelink
Other legendary creatures you control get +2/+2.

Blood Burglar

During your turn, Blood Burglar has lifelink.(Damage dealt by this creature also causes you to gain that much life.)

Mirri the Cursed

Flying, first strike, haste
Whenever Mirri the Cursed deals combat damage to a creature, put a +1/+1 counter on Mirri the Cursed.

Child of Night

Indulging Patrician

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
At the beginning of your end step, if you gained 3 or more life this turn, each opponent loses 3 life.

Mephidross Vampire

Flying
Each creature you control is a Vampire in addition to its other creature types and has "Whenever this creature deals damage to a creature, put a +1/+1 counter on this creature."

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Cruel Celebrant

Whenever Cruel Celebrant or another creature or planeswalker you control dies, each opponent loses 1 life and you gain 1 life.

Edgar Markov's Coffin

At the beginning of your upkeep, create a 1/1 white and black Vampire creature token with lifelink and put a bloodline counter on Edgar Markov's Coffin. Then if there are three or more bloodline counters on it, remove those counters and transform it.

Edgar, Charmed Groom

Other Vampires you control get +1/+1.
When Edgar, Charmed Groom dies, return it to the battlefield transformed under its owner's control.