HTC's upcoming Vive Tracker doesn't require base stations
HTC VIVE Focus 3 Wrist Tracker Top Plate
HTC Launches Aftermarket Face & Eye-trackers for Vive Focus 3 | Road to VR
VIVE Focus 3 Eye Tracker | VIVE Business United States
FULL BODY TRACKING - VIVE Trackers 3.0 - YouTube
3 Pack VIVE Tracker (3.0) - with HTC VIVE SteamVR Base Station 2.0 for VIVE Pro, Rebuff TrackBelt + 2 TrackStraps Full Body Tracking VR Bundle - Walmart.com