To start, you'll require a texture. You can use a crosshatch seamless texture, but any texture you want will do.
The basic manga shader
As the starting block for your manga shader, you might want to consider if you want your texture to slightly distort with perspective. The distortion is not as noticeable as if you just assigned the texture to a model, but it helps if you want to give a hint of curve to the texture you add to the model.
However, certain patterns benefit from having no texture, like scenarios where you'd use an actual pattern or screentone.
It's worth noting, this basic setup's texture does not zoom in along with the camera. So you may need to tweak the texture's size in its assigned Value node.
Advanced manga shaders
In this section, we'll showcase what you can do by tweaking the basic shader.
These shader, unlike its basic version, change size when the camera is closer.