New Materials Library script that creates an invisible layer in the scene, in which a sphere object is created with material from the selected slot, the script is useful when the slots run out of space.
Video how use https://www.dropbox.com/s/wepra6q86d6uxb9/%D0%9D%D0%BE%D0%B2%D1%8B%D0%B9_%D0%BF%D1%80%D0%BE%D0%B5%D0%BA%D1%82.mp4?dl=0