Day 28: Character you will never play again
I actually have a few. I never really need to play a fighter again. I had a few back in the day, they don't interest me all that much. Never really had the desire to play a barbarian.
Specific characters, well there is my thief Roscoe that will stay safely retired as well most of my characters from the 2e version of AD&D.
Actually there are a lot more than this since I like making characters and usually only run games these days.