Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Cordial Vampire

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

Shilgengar, Sire of Famine

Flying
Sacrifice another creature: Create a Blood token. If you sacrificed an Angel this way, create a number of Blood tokens equal to its toughness instead.
{W/B}{W/B}{W/B}, Sacrifice six Blood tokens: Return each creature card from your graveyard to the battlefield with a finality counter on it. Those creatures are Vampires in addition to their other types.