I can totally imagine vampires having blood type preferences.

Like, say, if a vampire comes up on a human and starts to drink, they could spit it out because it's a blood type they hate the taste of. Or if a vampire prefers Rh-negative, they would probably be excited when a human has that.

There's obviously more than the common blood types, but let's just use those for example. Maybe some could prefer Type A for having a rich flavor. Or Type O for being salty.