This way of shading uses no post processing or double meshes, making it lightweight and viable for mobile platforms. Available as material functions and master material.

Documentation

Showcase Video

Contains

• 2 Materials + 46 instances

• 6 Material functions

• Overview map

• 14 halftone textures

Overview Shader

• Unlit Opaque Material

• Base color, either a solid color or a texture, adjustable in brightness and panning

• Cellshading, adjustable in color tint, steps and amount

• Normal map input, adjustable in texture and strength

• Comic halftone, adjustable in tiling, projection, color and amount

• Outline based on texture or solid color. Adjustable in texture, width, panning and mask

• Specular highlight, adjustable in size, position, sharpness and color

• Rim lighting, adjustable in size, color and sharpness

• Day cycle and sun color reaction, adjustable in night tint

Notes

• Highlight and shading based on directional light

• Outline is best suited for rounded objects

• Shader doesn't get affected by objects blocking the sunlight (As far as I know, Unreal doesn't have a way to sample shadow maps in the material editor. If someone knows more, please contact me so I can upgrade the shader.)