On the old forums we had a nice topic on this for a while.
Not too much activity in the space due to the hardware requirements and locked down Meta Quest store, but there are some fun engine projects like LÖVR (intro video) and Godot VR support is apparently not too bad either.
But in the spirit of the old thread, please share some cool FOSS VR projects if you come accross them. For example:
LöVR Rocks, a RagnaRock compatible VR rythm game made with LöVR. Video of it.