Sorin, Imperious Bloodlord Sorin, Imperious Bloodlord saw a lot of play in Pioneer as a way to cheat massive vampires into play, like Champion of Dusk and Vein Ripper, so much so that it ended up banned in the format
1 Black Dragon
The Ozolith is another good support card, because its a one-mana Artifact that reads, Whenever a creature you control leaves the battlefield, if it had counters on it, put those counters on The Ozolith
Rarity-restricted Cubes will be happy to have access to another one-mana 2/1, with Human and Knight both serving as potentially relevant creature types in a wider range of Cubes
Skittering Cicada has similar utility but instead of slowly evolving, it gets trample and +X/+X where X is the mana value of the spell we cast, so it can become a huge threat from out of nowhere