The Fantastic Four:
* Mr. Fantastic (Reed Richards)
* Invisible Woman (Susan Storm)
* Human Torch (Johnny Storm)
* The Thing (Ben Grimm)
Spider-Man:
* Spider-Man (Peter Parker)
The Hulk:
* The Hulk (Bruce Banner)
Thor:
* Thor (Thor Odinson)
Iron Man:
* Iron Man (Tony Stark)
Daredevil:
* Daredevil (Matt Murdock)
Doctor Strange:
* Doctor Strange (Stephen Strange)
The X-Men:
* Professor X (Charles Xavier)
* Cyclops (Scott Summers)
* Jean Grey (Phoenix)
* Beast (Hank McCoy)
* Iceman (Bobby Drake)
* Angel (Warren Worthington III)
Other notable characters:
* Ant-Man: Hank Pym
* Black Panther: T'Challa
* Silver Surfer: Norrin Radd
* The Silver Age version of Captain America: Steve Rogers
* Nick Fury: (though he was created by Jack Kirby and Stan Lee)
This list is not exhaustive, as Stan Lee was involved in the creation of hundreds of characters over his long career. His influence on the Marvel Universe and superhero comics as a whole is immeasurable.