This is an odd one to me because I do not tend to make characters unless I play them (I did make a bunch of Shadowrun characters back in the day though). I also am usually the DM; the only games I have played as character in over the past 20 years have been non-D&D games.
So I'll turn this into a "Favorite Character I Wish I Could Have Played More"...
Miles (last name forgotten). Fighter/Swashbuckler.
Miles was a devil-may-care, swashbuckler who loved to live life to the fullest. There was no danger too great and no task that could not be accomplished. He was also one of the most vile persons on the planet. He wasn't evil for evil's sake, rather, he was exceptionally vain and selfish. He felt the world revolved around himself. He also liked to be in charge and if he could not be then other people must suffer.
I played him so he would not conflict with the other party members, but he was a cruel individual to the NPCs. He was truly horrible to women; one time he was about to bed one only to leave at the most moment saying she was too ugly. The height of his vanity and cruelty was when he went to bed a princess and she spurned him (rightly so). He decided then and there to create a war between her father's nation and the neighboring kindomg, all to get revenge on her; he would see her kingdom destroyed for his own petty vengence.
Unfortunately (or fortunately) the campaign ended the next week and I never got to see how far I could push Miles.