It's been a while since I moved up the stack to frontend development so I don't remember most of them but the primary one was the Saturn PCB toolkit [1]. There was one that we used in place of Saturn PCB toolkit that was far easier to automate but I can't find it now. I wrote lots of custom scripts to turn Excel formulas into Altium rules and there were quite a few crappy WinForm apps from fabs.
Edit: Nowadays I only do electronics for personal projects and since I stick to three fabs (a local one one I've got a relationship with and two Chinese specials), I've just got a few manually created DRC templates per fab, # of layers, and max signal speed with a few templates just for RF that I got from a mentor.
