Request to add support for hand tracking to Valve Index, and the Vive Headsets.
Possible implementation using mercury hand tracking: Monado / Utilities / Hand Tracking Playground / mercury_train · GitLab
The hand tracking plugin should already work with anything that supports the XR_EXT_hand_tracking extension, which Mercury does. I think it only works on Linux through the Monado runtime currently though.
The Mercury developers are working on writing a SteamVR driver for it, so it should be usable with the regular SteamVR runtime under Windows when that is complete.
According to the Unreal Docs, only HoloLense and Oculus is supported in the OpenXR Hand Tracking plugin (the main XR handtracking plugin). Making Interactive XR Experiences in Unreal Engine | Unreal Engine 5.1 Documentation