Well.. I forget when but it was certainly a long time ago, but I was playing this MMO called Mabinogi and I wanted a cool sounding name, so I brainstormed for about an hour and got Meyling. It sounded cute so I just kinda stuck with it. Also it reminds me of Hong Meiling from Touhou (a favorite character)
If I can't use that name, I usually call myself Mizuli. Strangely enough, it was also from brainstorming a name on Mabinogi. I was gonna be a Battle Alchemist who specialized in Water so Mizu and I added the 'li' part cuz' it sounded cute (and wasn't taken. EVERYONE uses the word Mizu).
Recently I've adopted the name Crow, but I only use it on things such as Discord, Steam, etc. because there isn't a 'username taken' system to them and I can just use whatever name I want. I like crows, but it also came from a character I made up (Prince Crow). Basically to summarize him, he's a crazy dictator of a country called Skyvania and he outlaws dumb things (like cars) to keep his people safe.
I would explain more about all that but it's off-topic and I doubt anyone cares. :P
I go by more names but I doubt anyone would want me to go on and on. unless you do then I will edit this post i guess