I like doing silly mono teams(not of type a lot XD) and this may be one, what are the pokes have to work with?
Let's see, what comes to mind when you think of pirates?
sea creatures, treasure, seabirds, sea monsters/mythical creatures, storms, and swashbuckling.
Let's see who fits these categories:
Sea Monsters/Mythical Creatures
Obviously I didn't list everything, but there is a character limit.