Below is a code example automating Photoshop to:

1. Create layer sets named according to the Unity Standard Shader map names.

2. Save these layers sets as PNG files with automatic naming conventions appended.

 

For things like the Metallic map which stores the Smoothness in the alpha channel, there are separate layer sets for Metallic and Metallic Smoothness. This allows artists to easily paint in each set without having to switch over to an Alpha channel.