after a very long time I found some time for my old Receptor rev.C. And here are some unsupported plugins:
1) Cakewalk Sonitus:fx suite
I'm using this suite for a long time in my Sonar 8 on Windows and I'm very satisfied with them. I copy a VST version to my Receptor and it works very well. You can import and save presets, very low CPU usage, GUI is working like a charm...great

2) ZynAddSubFX
My favourite synth. It works on Receptor 1 as I report few years ago (the old VST version not Zyn-Fusion of course) but GUI is useless. But you can export your presets from computer like a *.fxb and copy to the receptor. I'm using this synth alive for a few years and no problem on stage at all. Some presets has a higher CPU usage but you can turn off the reverb and other effects and use another one...
3) Rehearse VST
I'm very disappointed because this plugin "has been designed for the Muse Receptor" but it doesn't work

others: Zebra 2 (it is useful, some minor stuff with GUI, you can save and load presets...), G-player (it works very well but you cannot save and load presets so useless for live playing), Edirol Orchestral (it works very well but you cannot save and load presets so you can use just 16 instruments for live playing), Sylenth1 (it works but very slow GUI but you can save and load presets...), VST generated by Maize Sampler did not work...
Receptor rev.C is quite old hardware but still very usable for live playing... maybe its good time to release Muse OS like a open source

Btw: Does anyone here using Seelake AudioStation (MiNi)?