Our secret mary-sues, you say?
Well, this is going to have to take some thought, as I don't have anything as blatant as in this thread.
This just counts standard games, not 'Okay, so we're gonna play as Gods in this game, and basically make a world, etc.', right?
I guess I can think of 3 candidates:
1) Sharana the Vixen, a female bard half-werefox (had the ability to turn into a normal, non-magical fox, gave up all her half-elf racial powers for it) who was the illegitimate child of a minor Baron. This was back in 2e, when werefoxes were all beautiful chaotic evil elven women who could transform into a silver fox, and had spell-caster powers - one seduced the Baron, got a child off of him and, when the kid did not show any of it's mother's abilities, used it to shame the father, crashing a major banquet and revealing the entire tale, casting doubt and dishonor upon the family.
So Sharana grew up being pretty much despised by most of the nobility and her 'mother', though well loved by her father, and eventually decided to head off to clear the family name of the dishonor that her existence stained.
Captcha, have you been reading my old character sheets?