e: This is a more recent version of this shader.
Been taking a break from what I was doing by playing with some shaders.
So I went ahead and I wrote this deferred cel shader. This is all about shadows and deep contrast. Then I strapped it to a post-processing stack to further heighten the saturation and contrast levels and grabbed some asset store models for the sake of actually having something to shade.
Obviously, there are some minor issues in these screens - this is a very dramatic shader and the stock assets I've haphazardly glued into the lighting test here weren't exactly meant to be used this way. But I really like the way the lighting behaves here, I think - in particular, the second shot demonstrates what I was going for quite nicely.