Best 3rd Party Pathfinder books

[Yora]

I'm curious. Of course I know about Dreamscared Press' Psionic Stuff, and I have the very small, but very excelent Secrets of the Oracle pdf, but that's pretty much it.
Anything else one should really know about?

[Novawurmson]

I picked up Secrets of Pact Magic and Villains of Pact Magic recently, but they're actually 3.5 products (even if they have PF conversions readily available). Lots of great stuff in them, but I would recommend checking every feat and class carefully before allowing players to use it. For every brilliant and unique spirit there's an odd inclusion somewhere else (i.e. a feat that essential Expanded Knowledge for spellcasters, which may or may not be ridiculously overpowered for your play group and level of optimization).