Gold, Copper, Brass, Silver, Chrome, Steel, Aluminum, Platinum, Titanium, Tungsten, Carbon, Nickel, Bronze and Iridium. Painted Metals, Wood, Pearl, Emerald, Marble, Glass and Iridescent.
140 metallic gradients and a few other things:
Gold
Copper
Brass
Silver
Chrome
Steel
Aluminum
Platinum
Titanium
Tungsten
Carbon
Nickel
Bronze
Iridium
Others: Painted Metals / Wood / Pearl / Emerald / Marble / Glass / Iridescent