This thread was wildly helpful, and exactly what my DM needs. I compiled the majority of these suggestions into a printable PDF, available here: 
https://drive.google.com/file/d/1JGlspI6s_RmqXFNlKTjNbZiCUUcWFUAA/view?usp= sharing
I also posted it on Reddit: 
https://www.reddit.com/r/Pathfinder2e/comments/1id1yg2/recalling_dubious_kn owledge/
All credit goes to you guys for the excellent ideas. I am willing to take the post down if there are objections, I just thought it might be useful to other DMs as well. Thank you very much.