Been thinking about trying something like this out for a long time. Making a filter/switch that can take a more realistic material and convert it to a more painterly look similar to anime backgrounds.

Nothing too crazy just takes the base albedo and levels and quantizes it. Another set of nodes involve a brush stroke custom node that is ran through multiple tile samplers. These samplers also sample the color of the quantized base albedo which is then blended together. A similar process is done to the roughness, normal, and ambient occlusion.

There can a bit a of variance and sometimes I have to tweak a lot of the parameters in the filter to get something compelling. Other times there's just not enough going on in the albedo of the base material to derive the paint strokes in an interesting way. Future iterations may include more additional brush stroke controls outside relying on the base materials albedo.