Wow.
Had to go through some ancient internet pages to find what I have been known as.
My very first username ever, before I knew what an internet was, was on Neopets, at the age of 10. It was
Asher199.
I then used that same one for Runescape in early 2003, when I was 11, later jettisoning it in favour of Asher198. (Why? I don't know.)
I used to browse a little finnish indie racing game by the name of GeneRally's forums, under the name "Ungoliant4." Because giant spider.
This was ~2004. Ungoliant made just one contribution, a tiny wee three-polygon car. That forum is no longer existent, replaced by a new one long since. (Generally is ridiculously light on system requirements; its cars can have no more than 40 polygons.)
Later on, I used Ungoliant on
Crankeye / RMRK, then replaced that with Fenrir, starting up a little thread on a game that I was making circa 2006 to try and learn the RPG Maker series. It was tough. I never posted again after submitting my idea and having it shot down. Neither user is findable.
I also began playing AdventureQuest at this time. I had two characters, a Guardian called Fenrir, and a f2p called Sticky who was promptly deleted (as they do to free players after a set time not playing.)
After that, I really only continued with Asher198. I made various new accounts on Runescape, among them another "Ungoliant4", "Dr Bootsy", "Axen Renai".
Of them only Axen received half hearted attention.
Until I really began to use the internet in earnest again in 2009, I started playing World of Warcraft on a private server. There were SO MANY NAMES. My username was 'Harya', like a garbled version of 'How are ya?'. I had various player names, so many that I'll list them here. I should be able to find our old guild website.
Aha, found it. Our recruitment video, made by one of our 14 year old members. And our other site after we swapped servers. Nismo was my first, a friend had made his character on the same server and called it "Mugen", Mugen being Honda's racing unit I named mine Nismo, for Nissan.
Just because we both played shamans.
Leitdor was my Troll Warrior; pronounced "Light-door" but most people called it Leetdor. Pretty cool dude.
If I remember right, I show up in that recruitment video as one of the shamans, on Nismo.
Varok, Orc Hunter.
Elyn, Blood Elf Paladin.
Illius, Undead Priest.
Haemonoth, Orc Death Knight.
I think that that's all of the world of warcraft ones.
I remember planning to swap Asher198 to a newer name, after going through a series of names:
Llansing, Reudh, Ruadh, Rauthaz were the frontrunners; Llansing was just gibberish, Reudh was a bastardisation of Ruadh (gaelic for Red), and Rauthaz was proto-germanic for Red. See a theme here? I never ended up changing it, but more or less everywhere that I started calling myself Lord Reudh or Reudh is a result of that.
(Oh, and I forgot, in my early SA-MP days I was [AS]Dincht).