Where can I find the default Gmod materials?

Is there any place where I can find all of the materials used in default Garry’s Mod?
When I went to garrysmod\garrysmod\materials, it was all just custom materials from servers and stuff.

Use http://nemesis.thewavelength.net/files/files/gcfscape185.exe and open the garrysmod_000.vpk garrysmod_001.vpk etc. Also look in CS:S vpks for materials 95% of people have