2018.x SBSAR Files (Will Be Fixed At Some Point...)
.sbsar files won't work in 2018.x yet.
Copy This To That (All Versions)
If you copy all actions on a script that has a lot of "Procedural Materials" on it, it'll take a long time to complete. This is because Unity is doing everything twice, in order to save the changes. It's an annoying thing, but just be aware that it'll take a while to complete. Uncheck "Save Changes" in the Options area of the latest versions of the script to speed this up. But if you quit, any changes will not be kept.
Mass Exporter Won't Work (5.4.x)
[LATEST: 5.5.0b6 has a fix! I've not yet tested it, but I've been told it's fixed! So 5.4.x will *never* work with the Mass Exporter, but 5.5.x seems like it will :D ] https://unity3d.com/unity/beta/unity5.5.0b6 Currently "Mass Export" doesn't work in 5.4.x because of a Substance bug that adds " (Clone)" repeatedly to the end of the file name. Allegorthmic is aware and is working on a fix for a future 5.4.x update. Current 5.4 versions will never work with Mass Export, though. :(
Advanced options include the ability to completly replace the real-world "material" with a new one. For instance, metal can be changed to wood, or leather.
The included "Texture Customization" demo scene, with the "Copy This To That" and "Mass Exporter" inspector scripts make it easy to customize and -- with a single click -- export your textures into game-ready materials.
Adjustments can be saved as Prefabs, or coded during gameplay. This way, players would be able to customize the look of their characters, or spawned enemies can be created with randomized values, resulting in a nearly infinite number of unique looking bad guys.