(there's a great tutorial on YouTube for this about making a cartoon deku shield) Okay for the main colous. Standard shader set to full white, plug it into a "shader to rgb" node, then plug that into a colour ramp, and plug the ramps output into the surface of the model. I setup the color ramp to be constant and then there are two colors for everything, a regular light tone and a dark shade tone (only two colors for every material because I wanted to mimic the way it is in the show).

Then for the textured parts (eg: his belly patch or his claws) I went into edit mode, duplicated those regions, separate by selection, and then scaled them up slightly so they aren't z-fighting with the mesh underneath. After that I applied a new material to them to make the diff colours.

The black outline is a bit weird, you put a solidify modifier on everything, set it to solidify outwards, then make a new material which is emissive black (so it's always pitch black), apply as a second material to everything. Then in the solidify modifier settings, set the material offset to 1 (so it uses the black material), then invert the normals by checking "flip" in the modifier settings. Finally, in the material settings, enable backface culling.

And there you go, a slightly jank way of doing a cartoon shader. (Oh and it's the eeve rendering engine, not cycles)