Titanium is naturally a grey-silvery metal, but has the ability to be anodized in several colors as well as black diamond treated for a glossy durable black look.
Tungsten is a similar grey-silver colored metal-ceramic that can also sometimes be found treated with some black coatings for a shiny black look.
Gold is usually 'carated' mixed with other metals to add durability due to its natural softness. These other metals can alter the color of the gold to make softer yellows, whites-greys, pinks and other more recent colors.
Platinum is a whiter silver color than titanium.
Silver has a very white silvery look.