For adventures, I recommend ZEITGEIST and Way of the Wicked. Honorable mention to the comically cruel Rappan Athuk.

For systems, Gramarie right from these forums. Actually the reason I started lurking here years ago. Sigh, if only someone would publish it professionally... accessing the material right now is very scuffed.

I second recommendations for PF 3rd-party supplements like Ultimate Psionics, Akashic Mysteries, Path of War. I'm not familiar with the Spheres system but I know it's very popular.