Not sure if there already is a fic like this, but I would love to read a Mr and Mrs Smith-ish Johnlock AU. Not necessarily assassins, just something where they are both married but leading secret ~BAMF lives~ on the side, and each thinks the other is a "normal" person. Maybe to fit the Johnlock bill, they can be secret operatives or spies instead of assassins? (Or even superheroes, I'm just saying). And in their "normal life" role, Sherlock is a scientist, and John's a doctor? And each wishes to protect the other from the side that they think will horrify their partner, but then finally the truth~ comes out and cue them being BAMFs together! I don't know, just throwing it out there!:D