Anyone know of any games based on the Pathfinder SRD? They let everything out there for free and yet I've never heard of a game based on any of the Pathfinder stuff. Not that I'd want anything based on Pathfinder but I am curious. It's like Darwins dead-end on the open gaming license front. It was huge for awhile, but then when folks started making their own everyone went in a different direction.
Assuming you mean PF2...
PF2 's ecosystem does not lend itself well to making PF2 "alternatives" the way the 5e OGL does.
Firstly, because PF2's main marketing point is as an alternative to 5e. So not much call for an alternative to the alternative...
Secondly, PF2's game system has very tight leveling math. The entire gameplay experience is designed around encounters within a 1-2 level band of the PC's current level. Deviate from that and you instantly go to a total cakewalk or TPK.
Naturally, this does not lend itself well to system hacking, because you must account for the tight system math not to break stuff.
Not that PF2 doesn't have some decent ideas in it. But by the nature of its tight system design one is more likely to port those ideas into another OGL/D&D system than doing anything the other way around.