I used this username generator for another game, they have creative and unique usernames:
http://www.spinxo.com/Btw, I usually have usernames with the letter "x", or they start with "ii". I'm more less aesthetic, and aesthetic usernames sounds really cool.
If you are interested, aesthetic usernames start do not start with high key. There are a lot of aesthetics, you choose.
Anyways, I'm going to give you some ideas c:
-moelai
-dustyrxses
-iiestheticss
-axsthetic
You can also have aesthetic usernames with a name you choose, for example, Sunny:
-justsunny
-simplysunny
-obviouslysunny
I will give you some ideas from the generator:
-CreamConquer
-Geospec
-AlxeVxra
-Sxnnyside
-Itz_Me
Hope this helped ya!