Once in a while, all the Sherlock AU John Watsons get together for drinks.
Wherein Harry Watson meets Sally Donovan and falls for her, John brings Sherlock home for a Watson family Christmas for the first time, and there are murders and awkward holiday moments enough to go around. (Sequel to May Your Heart Purr Like a Bumblebee)
In which Harry is the biggest Johnlock shipper: Harry Watson is back from rehab and temporarily staying with John and Sherlock. She and John warily begin to rebuild their friendship, and then she makes some observations about her little brother and his flatmate which throw John entirely off balance. John/Sherlock, humor, romance, drama.
Nobody knows the whole truth about Mary Morstan. With the possible exception of the British government. (S3 and beyond, through Mary's eyes, assuming that she is working for Mycroft.) Adventure, suspense, romance, friendships, and a happy ending. John/Mary, John/Sherlock, Sherlock/John/Mary (polyamory).
Sherlock may have misunderstood about there being limits. Fix-it/coda for The Sign of Three. John/Mary, John/Sherlock, John/Sherlock/Mary.