TrackIR - TrackIR adds depth to the PC gaming experience by enabling players to take control of the in-game view.
VeeR VR - Global VR video community
Eyeware Beam - Turn your phone into an eye & head tracker!
VRChat - Create and play in virtual worlds with others
FaceTrackNoIR - FaceTrackNoIR is only available for Windows-based PC's (sorry, we have to start somewhere) and...
Spatial - Collaborate from anywhere in AR