After Dumbledore's death, Harry searches for answers in the Pensieve. But something goes wrong. Trapped inside a memory, Harry finds himself back at Hogwarts in 1945 where he meets an 18 year old Tom Riddle teaching Defense Against the Dark Arts. (This story is not mine, it is by an ao3 author named paimpoint)

Harry gets sent into an alternate reality where he is asked to solve the mistery of the Chamber of Secrets. But Harry doesn't want only that, he wants to change the world. Or at least to give Tom Riddle a chance. (Not mine story is by an ao3 author named d_aia) (Take series)

Albus Dumbledore has been searching for Harry Potter for seven years, unknowingly he bumped into the eighteen year old, and stirs the hornets nest. Harry who is the leader of the underworld, vows to put an end to the manipulative old man and also has to deal with Voldemort who was encroaching upon his territory. SS/HP top Harry bottom Severus! will Sirius and Remus join Harry? By: DebsTheSlytherinSnapeFan on fanfiction.net