@bunni As far as I’m aware, the only application available under a FOSS license is #Papagayo (https://lostmarble.com/papagayo). But as I understand it, it is nowhere near a similar feature set to #FaceRig. Where FaceRig is closed source and run in realtime (and has a toolset specifically for streaming), Papagaya is under a GNU license and can only be used on pre-recorded audio. I highly doubt that Papagaya is going to be a good alternative for a #vtuber. While it is extensible, I don’t think that realtime animation is it’s core focus (if at all). There has been some progress with getting FaceRig to work with Wine on Linux, but your mileage may vary:
Good luck, hope that helps!