All time forever favorite fic is Put Up Your Dukes by saltyfeathers. It kills me every time and I’ve read it 5 or 6 times. It’s destiel set in canon and it’s told from Dean’s POV. The whole thing is really funny and Dean is incredibly neurotic. Cas is also a little shit and Sam is long-suffering and he’s got some good lines, too. I love the fic. It’s not too angsty or fluffy but it’s a fic I really love.
But, The Siren and the Sea Monster by @ltleflrt is my second favorite. I just love it a lot. Dean works for Cain and plays guitar, Cas is an octopus…mermaid…person…? But it’s really sweet and I adore it. Also, tentacles because I’m one of those people. And Cas asking Dean if he’s a siren is the cutest damn thing ever.