The ABO blood groups seem to have some personality correlates. They may relate to temperament more than any other aspect: Here are some examples: (these are separable by a blood test, of course, and many people already know their type and many celebrities have their types known. But some of these are just guesses.
ABO O are high temperament. They are quick to respond to others comments, hang with their tribe, etc. They like to participate in fusses and even fights.
ABO A are smooth and low temperament. For this reason they are often in leadership positions especially in democracies. They are well liked.
ABO B are low temperament but differ from ABO A in being less outgoing but instead more introspective.
ABO AB are more like ABO B but some act like A types at times.