Some examples :
( in no particular order, and not meant to be complete )
Sequential Fourm
( thread )
Athena NK5.5-301
( post )
Arturia MiniFreak
( thread )
Hydrasynth Explorer
( Hydrasynth thread )
Korg microKORG 2
( thread )
Yamaha Reface
( no single thread )
ESI XSynth
( thread )