Ultra Shader Converter (formerly UnityShaderEdit)
Ultra Shader Converter was originally created for a to-be feature in the Subnautica Nitrox (multiplayer) mod for masking colors on player textures. The project never finished, so I decided to fix the tool to get it up and running with the latest engine versions and fix broken decompilation support. It is pretty much hardcoded to only support DirectX at the moment however.
Anyway, this project is really old and hacked together as a POC so it's probably better to start over from scratch or something.