Exported assets are free to use commercially and modify.

ToonShader.js

ToonShader2

Layered cartoon shading

ToonShader2
Preview requires WebGL2. You can still download the demo.
Drag to orbit · Middle-drag to pan · Scroll to zoomOne finger to orbit · Two fingers to pan or zoom

Uses clear patches of color for a hand-drawn cartoon look with distinct light and dark areas.

Official source