Supernatural/Hellblazer (comics version): Dean/John Constantine.
This is a really cool crossover. Set just before the tv series starts, it’s Dean on a job in New Orleans without his dad and in deeper over his head than he’d ever have known. I really like this story because the crossover potential between two canon universes like these is so strong but also because John Constantine is in a whole different league than the Winchester boys never even knew existed. Constantine goes up against the fucking devil himself and lives to fight more demons another day, and that is so much bigger than Dean’s rock salt shotgun and gritty bravado have ever faced.