Exported assets are free to use commercially and modify.

ToonShader.js

ToonShaderHatching

Sketch hatching

ToonShaderHatching
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

Draws dark areas with crossing lines like a pencil sketch, adding more lines in darker places.

Official source