Hmm for mine it's like... I started using Rhonder back in like 2009 for all of my online accounts and stuff, but I honestly have no idea how I came up with it LOL Like the story is: I went to sign up for a MMO that year and my usual online name prior, Raguna (which was one of my OCs at the time, the main char in a story I was working on), was already taken. So I decided to use the rival character's name instead, Rhonder, which was available. Then afterwards I started realizing that Rhonder was barely ever taken on sites that I wanted to use, (where as Raguna was somewhat commonly taken) so I just started using Rhonder as my go to.
The thing is tho- I have no idea where I pulled Rhonder out of to be the name for that OC of mine xD I honestly didn't even know it was a real name until a few years back, so that part baffles me.
It also accidentally almost works as an anagram of my real name: my name is Alex(ander) Roth,
Roth - T (& rearranged) -> Rho
Alexander -> nder
Rhonder
completely unintentional, but it works~