The silvery carp in the little lake next to mistfall village used to have an instant respawn timer. I farmed all but one of my skyshards off of them. I don't know if it's been fixed or not yet.
"Do not look down, my friend. Even in the darkest of times, there is always hope... Hope for a better day, hope for a new dawn... Or just hope for a good breakfast. You start small, then see what you can get." ~ Covetous Shen