I'm no expert on shaders or lighting so I can't tell you if these values are realistic or not, but it's not everyday I come across sites like this so I thought I would share them.
http://www.nicoptere.net/dump/materials.html
https://resources.bisimulations.com/w/index.php?title=Material_templates
http://www.nicoptere.net/dump/materials.html
https://resources.bisimulations.com/w/index.php?title=Material_templates
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