Voyage! is a stand-alone campaign system for games set in the Caribbean during the mid-late 16th century. It is intended for use with the The Perfect Captain's Spanish Fury game.
Comic Book Plus has a collection of pulp pirate comics and stories.
Archipelago of Gold is a set of free wargames rules for use with the constructable, collectable Pirates of the Spanish Main ships from WizKids. From the BGG description:
These rules use the Pirates of the Spanish Main and a hex map to allow you to explore wild islands for gold, build large fleets, settlements, cities, forts, and train your crews to become superior gun crews. Get more gold back to your settlement, and you can build more than your opponents.