However, I think people should experiment with what I call “open source universes”, which is basically creating shared universes that are open source. Maybe even make some open source RPG system with it too, so we could have an open source alternative to the likes of D&D, WH40k, etc. At one point I tried to make something like this, but the issue was that it was based on an old webcomic idea of mine, which I started working on when I had totally different views on many things. Might revisit it with different ideas later on.

Haven't played any of those, but I think they (and more) exist for a long time already: https://wiki.rpg.net/index.php/Open_Game_Systems