[aeronaut]

The "classic" good pairing is to combine Cthulhu with Bites, since Cthulhu has classes but no races*, and Bites has races but no classes. That way you can be a Vampire Monster Whacker, or a Werewolf Professor, or a Changeling Cultist. There are other synergies as well, and the combination of the goth feel of Bites and Lovecraftian feel of Cthulhu blend nicely. And of course, when bats and goths come together, it's a monster party.

But it's munchkin, and you can do whatever you like with the cards you buy. You want to blend Supers and Pirates, powers to ya, matey.

Regards,
aeronaut

*The "Monstrous Heritage" card can count as a race, but it's a rare card.