TF2 Gold Materials
Accessed from Material tool, materials included (previews are gray icons, hover over them to reveal tooltips):
Material
Tooltip
Australium Gold
gold_tool/australium
Goldcube
gold_tool/goldcube
Saxxy Gold
gold_tool/saxxy
Does not require TF2.
If gold materials look brown for you, make sure cubemaps are enabled (mat_specular 1 in console).
Materials/textures – Valve, GCFScape – Nem.