This is a utility PBR node for some of the more common materials. It includes settings for dialetrics, metals, glass, emission, and plastic. Included in the .blend is a small node group with some presets for basic metal colors based on RGB values as well. Adjust the designated slider from 0-1 to change the current preset.
Great node setup. I should come in handy for those who wish to create realistic renders. Great job.