The Hammond company probably made the most overall contributions in laying the foundations for modern synthesizers of any individual company. They in fact developed what is considered the first keyboard based synthesizer, the Novachord. Their involvement after that in synthesizer production was the limited mostly preset based Solovox; a monophonic takeoff on the novachord that used a small keyboard that could be shelved under a piano to give a solo voice to the pianist and then finally one very limited production solid state synth in 1974 the 102100 which was still almost entirely pushbutton but offered many more preset envelopes etc. Here is the official history site.
Products:
Novachord Solovox 102100