Leap Motion Orion - Next-generation hand tracking for Oculus VR
TrackIR - TrackIR adds depth to the PC gaming experience by enabling players to take control of the in-game view.
Oculus Medium - Sculpt, model and paint in virtual reality on a 3D canvas.
FaceTrackNoIR - FaceTrackNoIR is only available for Windows-based PC's (sorry, we have to start somewhere) and...
Tilt Brush - Paint in spaces around you with Virtual Reality
linux-track - Linuxtrack is a software bringing headtracking to Linux and Mac OS X.