When I think of shareware I think of id Software, Apogee, McAfee and PKZip. It might not be official but to me that is as close to pioneering as it gets.
* "more or less" because the business structure is more complicated than that and there was still an Apogee Software alongside 3D Realms, but for all practical purposes, what was Apogee Games became 3D Realms and then died due to the Duke Nukem Forever project.