So I am working on collecting all of the sublicensable RPG systems I can. My goal for 2026 is to write as many hacks as possible. Planning on making lightweight versions with low/ not art and making them Pay What you want. These are the ones I have so far.
Do y'all have any suggestions for other games are built with open licensing in mind. Bonus if you can list both a game like this and your favorite spin off from that game!