Redshift comes with a node to blend materials or shader networks together. The Material Blender node can be used when a material uber shader isn’t enough. With it, you can blend several materials by overlaying them together. An example would be creating reflections, dirt and smudges over top of materials to make them look more realistic.
The Material Blender in Redshift supports up to 6 coat layers on top of a base material. You can even make things a little more interesting by controlling the blends and mixes with maps.
Demonstrating such a technique is a tutorial from The Vertex Library, who who’s how you can blend materials in redshift based on their displacements. This can give you all kinds of interesting effects and can be used in a variety of ways. An interesting way to designate contributions.