Albus Dumbledore and Gellert Grindelwald are newly graduated and taking a quick tour of Hogwarts together during the summer when they stumble into a head prefect Tom Riddle. The sixth-year Marauders run past, desperately chasing after an escaped Moony who thinks this is a game and wants to play. Post-War Harry Potter watches all of this happen in swiftly mounting horror.

James Potter is in his fifth year at Hogwarts when he's kidnapped by a time travelling Sirius who just fell out of the veil. And then his adorable son arrives. Also Voldemort is still a thing. (James is an optimist though so…things could probably be worse?)

Harry thinks to himself; why not? So he picks up a little Tom Riddle and tries to indoctrinate the boy into following a Gryffindor approved set of morals. He grabs Gellert Grindelwald too because if he screws up with one, he still has another try. (Poor Harry never does quite understand that he's not the one pulling the strings.)

Pro Hero Ground Zero is attacked, originally meant to be de-aged out of existence by a desperate villain but is instead launched into his 14-year-old self. But Katsuki is a fucking pro so whatever, time to fuck up someone's day. And sure, maybe he's only one man, but that's why he conscripts the entirety of the UA student body into tearing down some criminal empires.

Sirens eat Merfolk - except Harry is a super cute Mer baby and his dad isn't so bad either and really, Remus, I can explain how this happened. (Remus floats in place with his arms crossed, staring Sirius down as the other Siren sheepishly lowers an unconscious James into their nest.)

Kakashi is six and lost behind enemy lines with a make-shift team of other chunin, desperate enough to try and summon his dad's ninken. Kakashi summons ANBU Hound instead.

A bunch of crossovers. Ch 21 (Otome AU): Tsuna gets stuck in an otome game except he's a genre savvy hardcore gamer. Reborn is sceptical Tsuna will last the week.

Reborn 'finds' a book that summons creatures from beyond the dimensional fold. The Arcobaleno show up. Reborn doesn't put the pieces together.

Kushina is nine months pregnant when she turns to Kakashi with a scroll. "Just in case," she tells him easily. "Worst case scenario, it's still just temporary. You'll hold the fox for a day -twenty-four hours at the most- and then when I'm good to go again we swap back." (but Kushina dies, doesn't she)

When Harry asks to go back in time, Death stipulates that he has no influence over bringing life – Harry has to come into the world the way everyone does. "Ow," James wheezes, hand coming up to his stomach. "Did someone just sucker punch me in the kidney? What was that?" [tl;dr Death goes full Zeus and the Marauders are pretty sure James is being possessed]

(A series of unrelated stories.) Ch 35: Reborn gets too deep into a joke and now everyone thinks Fon is dead when he's actually just chilling at Reborn's apartment. In true Reborn fashion he goes the extra mile and uses one of Verde's machines to ask his future self how he solved the problem.

Harry goes back in time to raise a young Tom Riddle - except Voldemort gets there first. (Tom is left in the dubious care of two not-fathers who occasionally try to kill each other.)

Sirius falls into the veil and James is the one to shove him back out. The Marauders then steal away Harry, half-heartedly recruit an irritated Snape and attempt to defeat Voldemort with absolutely no plan at hand but that's how they usually roll so it should be fine.

Harry doesn't want to fight the long-haired assassin, but he was terrorising the middle-schoolers. He might not even help things, it's been a while since he'd fought... but he did always learn best in the thick of things. That, and he has a particularly vicious Prefect as back-up.

In which Tsuna is hurt very badly by his friends, and in turn hurts them badly as well. However, the ones who end up hurting the most will be the suicidal fools that thought turning them against each other could ever end well.

Harry thinks it's all over; Voldemort is dead and everything is going to be fine. Fate promptly responds by backhanding him across the face, spitting on him, and then calling his mother fat. Harry decides that it's time to retaliate. (Where Harry missed a Horcrux and gets a visitor.)

Voldemort is not scared of dying, but he is terrified of Death. The entity does not understand love, but it understands obsession and patience and forever. (Written because Voldemort deserves someone… nice to spend eternity with.)

Harry didn't know how he got to be in the past, sitting next to a teenage Tom Riddle, but damn it if he wasn't going to get revenge. No matter how petty he has to be.

Voldemort visits Harry's supposedly hidden safe-house, seven years after the Light failed to win the Hogwarts battle, and has a polite chat regarding heroes and other such beings of fiction.

Voldemort is… confused. Potter is attached to him in the most literal sense and he won't let go.