The closest I've gotten to a "theme" was getting Don Juan (who was so named by the Humane Society) and then renaming the blackie I got to keep him company "Zerlina" (a character in Mozart's opera Don Giovanni). The rescue group called her Zana, so it wasn't that big a change. At the time I was thinking of getting a little boy kitten and calling him "Leporello," but that hasn't happened.... yet.