GGXrdShading
Guilty Gear Xrd Toon shading techniques demo, try it here: https://galloscript.github.io/GGXrdShading/index.html
GDC Talk where this techniques are described
GuiltyGearXrd's Art Style : The X Factor Between 2D and 3D https://www.youtube.com/watch?v=yhGjCzxJV3E