Okay I was curious so I actually dug out my game binder and counted how many systems are represented in there (which is equal to or less than the number of systems I've played - I'm not sure I have every character sheet I've ever used).
Final count was seventeen systems, and the system with the most number of characters is Shadowrun 4e (mostly because it's really, really easy to get TPK'd in SR, unfortunately)
Me, every time someone brings up the OGL fiasco: /opens trenchcoat to reveal Redbrick Earthdawn books/ Could I interest you in a high fantasty TTRPG with genuinely good worldbuilding?
(I've been bitching about D&D and d20 for like the last decade and have been lowkey annoyed at the resurgence in the last five years or so. I accept that some of this is that I'm a WoD kid, but also D&D is the least interesting system I've played)