Everything else (while the art has been greatly advanced) seems like a variation on these themes. Certainly Bill Lawrence, Seymour Duncan, DiMarzio, Floyd Rose and many others have widened the flow of this river of innovation. But as far as I know Les Paul's pursuit of the solid body is what brought all this to the fore.
From my perspective Leo Fender did three great things. He timed the start of business just right and he taught the world how to manufacture guitars. Gibson had an acoustic guitar background as did almost everyone else. However Leo looked at the solid body with fresh eyes. Bolt on necks may or may not have been introduced by him (they existed on other instruments) but he pulled together the art of manufacturing guitars like no one else. And of course, he created the electric bass.
In all this I also overlook the input of many players who helped develop various features and ideas. As an example, I believe Alan Holdsworth was one of the first folks to put a humbucker in a Strat (which was sometimes made out of lighter weight wood than a Les Paul) and started a revolution which can be seen in any music store today. The ES-335 and its variations and knockoffs are still extremely popular. Even the modern archtop, a very different instrument today than the ones built by Gibson, Stromberg, Epiphone et cetera, during those times has benefitted from the humbucker and piezo pickup development.
The instrument that I've played for the longest time is an Ibanez AH-10 which is Strat like, but with a single humbucking pickup in the neck position. It didn't come that way, and various experiments show on the pickguard. It has a fairly light basswood body, a knife edge whammy which has three springs tightened down and maple neck with a rosewood fingerboard. It's the classic story of finding an inexpensive guitar that with a little tweaking becomes something special. Yeah!