Our best chance to get a PBR friendly Cel Shading art style in Unity 5.6 is creating a new Deferred shader and a custom BRDF function. Here's are the steps needed to get it to work.
Finding New Style for Urban Environments
UE4: Detailed Texture Blending with HeightLerp and Vertex Painting
UE4 - How to Make Dynamic Flowing Water
Steam Mage Tower, Alex Serebryakov on ArtStation at https://www.artstation.com/artwork/steam-mage-tower
X Inn - 3D Model, Vania Astari on ArtStation at https://www.artstation.com/artwork/x-inn-3d-model
Airbattleship in flight by Blackadder02
Paysages 3d #3d #lowpoly