Adding new maps would (will) be a piece of cake. Thanks to Godot, I can add textures for Rim, Clearcoat, Anisotropy, Subsurface scattering, Transmission and Refraction.
But first, I have to understand what they are used for. :p
in Simple Terms, Subsurface Scattering Maps are Mapping of how color of an semi translucent material should change when light affects it. the most common example being human skin turning a pinkish color when light is shining. (ex.