Sula Metallic Topcat paired with Essie Loophole silver polish will give nails a glossy sheen. Minx nail coverings in a flashy color (applied by a nail tech) is a way to try a bold metallic.
A clear matte finishing lacquer such as Orly Matte Top instantly takes the shine away. Super-bright colors such as OPI Matte in La Paz-itively Hot make a big statement.