Twitch will let you change your username every two months
 

Starting today, you can change your Twitch username. What's more, you can do it every 60 days, and, seemingly as a shot at Microsoft and Xbox Live, it won't cost you a dime to swap from "FluffyJungle9991" to something a that's easier to commit to mem...

https://www.engadget.com/2017/02/24/...ry-two-months/