I'm just writing this off the top of my head, for now. Maybe we can get more in-depth later.
Buster Keaton
"When I was six months old, we're on some little town, a small hotel. And I fell down a full flight of stairs, to the bottom. They come running up, I sat up and just shook my head, shook it off. Didn't cry, so I knew I wasn't hurt. And Houdini says 'That was sure a buster', meaning a fall. That's the only time it was used. That meant a bronco buster or a fall. It was never used as a name. My father said 'well that would be a good name for him.'" He was given this nickname just five years before...
Buster Brown Buster Brown started out as a comic strip character. The creator sold the rights to several different businesses, including the shoe brand.
William "Buster" Collier
An actor, and friend of Buster Keaton. He and Louise Brooks were married for a while.
Buster Harding ("Hardy")
Cab Calloway's head composer guy.
Buster Williams
Erroll Flynn's stuntman, and friend. He wrote a book about his experiences with Flynn.
Buster Crabbe
Flash! AAAH! He'll save every one of us!
I couldn't resist. This is another actor, the man who played Flash Gordon in the original black and white TV series. He was also in a movie with W.C. Fields. Before acting, he was an athlete and a swimmer.
Buster Poindexter
Anyone feelin' hot hot hot? (feeling rather silly.) After becoming a one-hit wonder, this Buster also tried his hand in acting with the crappy film version of "Car 54, Where Are You?"
Buster Bunny
...of "Tiny Toon Adventures" fame. He wasn't my favorite character, but he was the lead, and voiced by Charlie Adler. No relation to Babs.
Buster Bunny #2
White anthropomorphic bunny in "Arthur," the PBS cartoon based on the books about Arthur the Ant-eater.
Busta Rhymes
Energetic rap star, and Co-star in "Shaft". WOO-HA!