To add to what cybereality said, another optimization you likely want to make with VR is limiting the use of screen space effects, specifically Screen Space Ambient Occlusion (SSAO) and Screen Space Reflections (SSR). Instead, try using textures to "simulate" some of the effects, like baking the ambient occlusion into a texture. Additionally, any tips and tricks for optimizing performance that applies to mobile devices is probably applicable to VR as well and may be helpful to look at.
As Megalomaniak said, a specific category for VR is likely not going to happen right now, as there is just not enough discussion to justify it having its own category. The 3D category with the AR/VR tag should suffice for most purposes.
