One of the great things about Paizo and the Pathfinder RPG is their willingness to try new things, be a little experimental, and not just put out more and more of the same. Third Edition D&D became glutted with huge amounts of feats, spells, and prestige classes. Virtually every book seemed to be made up of mostly those three things. Later books started adding new base classes, but it was still more of the same. Only very late in 3.5’s time did the books start to try new things, but those tended to involve entire replacement systems (such as Magic of Incarnum or Tome of Battle) rather than things that simply gave new options for existing material. Pathfinder has had its share of new feats and spells as well, but virtually right from the start, Paizo began to pull back on the amount of prestige classes. Pathfinder may have started as a revision of D&D 3.5, but it very quickly began establishing an identity of its own by expanding the game in new and creative ways. The GameMastery Guide added things like haunts (originally from the Pathfinder Adventure Path series) and updated them to the new rules. The Advanced Player’s Guide introduced archetypes (which admittedly there has been a bit of a glut of since) as well as new rules options for any character, such as additional types of combat manoeuvres and traits.
Of course, the game is built upon certain expected tropes, and these haven’t been abandoned. There have been new classes (and while the added 3.5 classes tended to be “fixes” for existing classes, these have been completely new classes that expand the game instead of rewrite it), new feats, new spells, etc. And of course, there have been new monsters. Each fall since the release of the CoreRulebook, Paizo has released a Bestiary—until now (well, this fall does have the Inner Sea Bestiary, but that’s part of the Pathfinder Campaign Setting line). Last year saw the release of Bestiary 3. That makes three hardcover rulebooks full of monsters—hundreds of monsters. I’ve heard it said and seen it written that you can never have too many monsters, and in a sense that’s true. Monsters are fun, and the fun of seeing new creations and variations will never die out. They can be sources of inspiration as well, forming the bases for endless adventure ideas. But in another sense, it’s completely false. You really can have too many monsters. In the first three Bestiaries alone, there are more monsters than anyone can reasonably expect to use in a lifetime of gaming, and that’s not including the numerous new monsters added in Adventure Path volumes and various other sourcebooks.