Well there's a series right now that I really love. Its very AU, focusing on a more angelic plotline through seasons 5 and 6. Its got an OC that you get very attached to. Its got whump and romance and suspense. Its very good.
Little Girl Lost is the first of 4 stories. ( story
2, 3, and
4) 4 not complete and is being updated regularly.
Broken Wings is a good one that features Cas, Dean and Sam whump.
Waxing and Waning is a Dean whump fic. Dean's dying and Sam is rushing to find a cure.
Superheroes is a really sweet oneshot.