As a streamer, if you want to grow your channel, your Twitch username is of the utmost importance. A name that's chock full of signs and symbols will make it hard for people to find you. So you're better off choosing a Twitch name that's catchy, simple, and that reflects either who you are or what you want your persona to be.
But wait! Before you start building your Twitch brand, you need to make sure the username you've come up with isn't already taken by checking its availability on BrandSnag. The BrandSnag Twitch Username Checker will tell you right away if your chosen name is free to use. You can check as many names as you want to for free. You can also check a name's availability on different social channels. This would allow you to have the same username on Twitch, Instagram, and Twitter, for example.