Cordial Vampire

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

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.

Cruel Celebrant

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

Mathas, Fiend Seeker

Menace
At the beginning of your end step, put a bounty counter on target creature an opponent controls. For as long as that creature has a bounty counter on it, it has "When this creature dies, each opponent draws a card and gains 2 life."