[Idol Thoughts]

With the 2020 Summer Olympics taking place in Tokyo, it'd be a prime opportunity to use it as a theme that year.

Fairly evident, the colors of the primary five would match the Olympic rings: red, black, green, blue, and yellow. The sixth would be white, as it's also an Olympic color. There'd be a trio of auxiliary rangers that would be gold, silver, and bronze.

With a general athletic theme running through the season, humanoid mecha would make sense.

For mecha, weapons, etc., it'd pull inspiration from whatever popular events possible. Most would probably be longstanding events, but any event that's new to the 2020 Games could possibly lend itself to the sixth.