For metallic thread ProWrap is the industry standard. It features a strong core that will not fray and the metallic braid has been pressure dyed for excellent color saturation. The thread is strong enough to use as a main wrap or trim bands.
There are a number of gold metallic threads on the market. Some are blazingly bright. Calcutta is different. Calcutta a more subdued gold, while retaining the classic contrast against dark colors.