Blender: How to Combine All Materials Into 1 (Answer: Replace with UV Map/Texture)
Thanks to RavenWaffle for the model and question
This is Blender 2.82a, works the same in 2.82, 2.81, 2.80, 2.8 and surely 2.83, 2.84, 2.85, 2.86. and if you use cycles the same in 2.7 aka 2.79 aka 2.79a aka 2.79b. Texture from Ravenfield Tool Pack