Paizo has released their Bestiary 4 book for Pathfinder that adds more than 300 monsters to the lexicon.
From the release:
Something wicked this way comes from Paizo Publishing, LLC, publisher of the world’s best-selling Pathfinder Roleplaying Game, and leading publisher of fantasy RPG accessories, board games, and novels. Just in time for haunting Halloween gaming, Bestiary 4 is out now, available in hardcover (MSRP $39.99) or PDF-format from paizo.com ($9.99).
Pathfinder Roleplaying Game: Bestiary 4 introduces more than 300 new monsters for use in the Pathfinder RPG, including creatures from classic horror literature and monster films, such as blood-drinking nosferatu, gargantuan kaiju, mythical demon lords, and even the Great Old One, Cthulhu!