yugioh crow deck 5D's Duelist Pack Single Card Blackwing Mint / near mint condition trading card Yugioh Orica - Crow Hogan

If you really want to keep your bloodsuckers full and charged up, this is the card for you

On the other hand, do the deckbuilding requirements undo the power of this mechanic

Two underrated constellation cards in EDH are Nylea's Colossus and Thoughtrender Lamia

There is less than a 3rd of the deck as instant or sorceries so you are only going to hit 1 in 3 on average, and there are minimal legendaries in the deck to untap it

I genuinely think that could be alleviated if Wizards ever printed another Vampire commander in his color combination, but its impossible to say right now (and they apparently are hesitant to do it because they dont feel like it would be wanted)