I guess I'd throw in Larry Lieber. He's certainly not a big name, but he's credited as co-creator of Iron Man, Thor, and Ant-Man.
This is enormous. Not only did Ditko give us Spider-Man and Doctor Strange (as well as The Question, and Squirrel Girl, and Lord knows however many I'm not thinking of), but his storytelling and imagery were unmatched. I could look at his work in Strange Tales all day. Damn.