For some reason I thought he created Superman
Probably one of the few first tier superheros he didn't have any involvement with

I always tended to enjoy Lee's hero's more than most of the DC ones because they tended to have a bit more meat to the character, the flaws that meant they weren't invincible and could act in morally grey areas or even at times become "bad guys" for a while (and even his bad guys often had their good sides and a background).
I was never a huge comic book fan, but always enjoyed the x-men etc when I read them*, but Stan Lee was always one of the names I remembered and enjoyed reading his work, I remember my Brother-in-law watching Mallrats with us and getting excited at Stan Lee's appearance in that.
He was also always one of those guys that seemed to have a lot of time for his fans, and understanding of exactly why people liked his characters and the knack of creating characters you could identify with (mutants being the outcasts/racism analogies, or the kids that were different at school, whilst looking back Rogue could be seen as the youngster with some diseases that could be transmitted through touch/intimate contact).
I suddenly want to pull out some of my old comics and read them again, I don't have time for that.
*Going back to the 90's, I collected the Image type comics (gen 13, spawn, Crimson, Battlechasers), my Brother collected X-men etc and my BIL collected vast numbers, so I got to read a lot.