Often the stuff I find on this site has a lot shallow characters stuck in plot contrivances that are forced by the author to try to maintain interest.
This list, in my opinion, is a list of stories where the characters and their struggles are believable within the confines of their universe's logic, and don't become too outrageous.
Order is roughly organized with what I believe to be better quality closer to the top, but nothing is strictly better than the other. All of them are good in their own right.