Colors not used that much in Sentai

Super Sentai also has some colors that weren't always used and usually applied to extra members like:

Battle Fever J's Battle Cossack is the only orange ranger known so far. He was part of the regular roster since there were no additional rangers back where he came from.

Silver was the first color to be not frequently used. The color appeared first in Megaranger's Yuusaku Hayakawa then in Gaoranger's Shirogane, Boukenger's Eiji Takaoka and Go-onger's Mio Suto. Go-onger introduced the first female silver ranger. Did Tommy's conversation in the MMPR movie inspire this?

Although in the PR side, the King Ranger was called the Gold Ranger (even if King Ranger was a black ranger), however the first official gold ranger is Hiruto Suto from Go-onger. The second would be Genta Umemori in Shinkenger.

The first and only purple ranger Retsu Fukami.

Commentary courtesy of Sean Akizuki's Sentai Blog.