Prosoniq
Prosoniq from Germany furst released FX for the Ensoniq EPS 16+ and ASR10 and later SonicWorx, they still produce VST Plugins which are underestimed (I assume they are still), one of their "side projects" was the Hartmann Neuron Synthesizer.
- the Key Person at Prosoniq is Stefan Bernsee who also has a Solo-Project developing with and on OS X