I am implementing the following extensions to add information to glTF so that we can use this as our main 3D file format.
ULTRA_triangle_quads: Used to store quad meshes in glTF.
ULTRA_material_displacement: Stores displacement mapping information in glTF materials.
ULTRA_extended_material: Adds extra information to glTF materials like shadow and tessellation state.
You can read more here:
If you have any suggestions or if you are interested in collaborating so that our applications work together better, please let me know. I do not know of any existing extensions that provide this data.