A trip down memory lane!
Counting rules sets only I count 20-21 then (thanks to buzzardo, I remembered Gangbusters). I count HeroWars/HeroQuest as one, but separate from RuneQuest as RQ is a completely different system though it, too is based on Glorantha. Similarly, I have HârnMaster 1, 2 & 3, but I don’t count them as three games.
I’ve played, or GMed almost all of them. Universe was IMO pretty much unplayable, V&V is the worst of the superhero games (again IMO and based on the fact I played it once 20+ years ago). Of the others I would not recommend Top Secret or Star Frontiers. I ran a short, but enjoyable Gangbusters campaign 20 years ago, I wonder where I’ve put the rules……..
HârnMaster
RuneQuest
HeroWars/HeroQuest
Fate
ADnD
Justice Inc
Champions
TimeLord (an alternative Dr. Who game and much better IMO than Dr Who)
2300AD
StarFrontiers
Universe
Villains & Vigilantes
Warhammer
Pendragon
Superworld
Earthdawn
TopSecret
JamesBond007
ArsMagica
Talislanta
Gangbusters
GOM