Boy, that could be a pretty long list! Time was, it seemed, there was a lawn mower manufacturer on every other corner, especially following WWII when our troops were returning to settle into civilian life again and suburban America exploded. It would make for an interesting study for sure.
Although there isn't much in the line of information on motorized reel mowers, there are a lot of links to be found on this site that might get you going.
You might find a book entitled "The Lawn - A History of an American Obsession" by Virginia Scott Jenkins, ISBN: 9781560984061 an interesting read. It traces the growth of the lawn care industry here in the United States, and there are a lot of references to lawn mower manufactures. There's a picture of pro golfer Sam Snead at the controls of a Toro Sport Lawn on the cover.
There was a lawn mower museum located in Crescent, Iowa at one time called Archer's Engines of Yesteryear. I can't find any web site for it, but maybe a phone call to them if you can locate one.
Something else that's kind of fun is going to Google Patents and looking up patents for different mower manufacturers. Here's the Eclipse patent for the handle on your Rocket.