Bonus points for any non-D&D or D&D derivative systems.
My first RPG was Palladium Fantasy way back when my grognard uncle invited me to his groups table. I still don’t really grok it, but it was pretty formative of my ideas of what an RPG could be. The lack of balance and extreme existential threats as part of ordinary encounters included.
Needless to say, I haven’t found a group for this system in a looong while, eheh.
I was explaining to an acquaintance the reasons why I was transitioning my group to GURPS from DnD, and she said she learned GURPS first and they’re the same. And I was just kinda gobsmacked that 1. she’d heard of it at all and 2. she learned it first.