Harry Potter bunnies
in which harry dies
1- ward theory:
The Dursleys are horrible people yadda yadda. Poor little Harry dies of starvation, beatings, and neglect before primary school. The blood wards around the property are overworked to protect unloving muggles, and thus treats Harry's death as a sacrifice. The horcrux attempts to prevent its vessels destruction (death) and as such Harry's soul is absorbed into the wards, instead of simply fueling them, and he begins living through them. the Dursleys proverbially sweep Harry's death under the rug and act as if nothings is wrong, eventually all but forgetting the entire thing. What exactly happens to Harry's body is up for takes. Dumbledore doesn't know anything because of observed incompetence (the wards interfere with magical monitors of Harry being alive if Dumbles had any pre-Hogwarts). Spirit!Harry grows up better adjusted from observing the positive changes that no longer having a scapegoat meant for the Dursleys. The Hogwarts admission letters are addressed to simply Number 4 Privet Drive. Hagrid is sent in an attempt to investigate, but leaves after finding no Harry, thinking he somehow had the wrong address or something. September 1st having passed with no mention our hero, Dumbles goes to investigate himself, and rips the fact that Harry has been dead for years directly from the Dursleys minds. Harry silently observes Dumbledore (nearly) have a stroke and leave listlessly, wondering whether he should try anything. Possibly Harry hitching a ride on one of Dumbles' many knickknacks and coming to Hoqwarts, or eventually finding some other way there. Or Dursleys leaving and putting the apartment on sale, only for it to be bought by magicals. If Harry goes to Hogwarts, then she (the castle) would be able to converse with Harry, and would assume the role of Harry's mother.
what happens afterwards up for takes.
2- ghouls & goblins:
the Dursleys are horrible people yadda yadda. Poor little Harry dies of starvation, beatings, and neglect well before Hogwarts. Accidental magic / the blood wards, and the horcrux prevent Harry's soul from vacating his body, turning it into some form of undead/demon/fey. "Reborn", Harry escapes before the wards catch on and collapse, or escapes and the wards eventually collapse. whether or not Harry claws through the fragile enough cupboard, or discovers a new racial teleport ability affects his future. Claws, and Harry becomes "feral" and lives in forests. Only speaking with snakes keeps him with a remotely human mindset. Teleport, and Harry would eventually find some form hidden community of those at least similar to him.
Minutia regarding the news of his death breaking, the search for him, and possibly finding him, and the consequences of all these are up for takes.
3- Deific Interference:
Harry being envenomed by the 1000s years old Basilisk was finally too much for the rest of the powers-that-be to be forced to accommodate via prophecy. Desiring to make the fate-manager suffer for their misdeeds regarding Harry, they let him live, or resurrect, but as the amalgam of, both Voldemort's horcruxes that were present, and basilisk and phoenix blood due to the venom and the tears mixing with the blood protection. most likely also give a massive magical boost via deus-ex-ward mechanic as shown below, as the other deities don't want to use the horcrux-link as an excuse to dodge the fruits of magical weightlifting. Harry wakes up extremely disoriented by influx of random memories a la Riddle, and starts being smart immediately. He does go to "report" to Dumbles', as not to do so would be the height of suspicious, but he avoids eye contact at all times. Harry also sees right through Ron's gitness and breaks that up, has a spine in general, starts exercising and studying, seeks to replace Hermione as the best friend; if not girlfriend, and re-evaluates his life in general. Returning to privet drive and examining the wards, surreptitiously slapping of the flimsy ministry surveillance ward, and setting the Dursleys to their place. Visiting Gringotts for inquiries over the summer, and putting things on the right tracks.
in which logic is applied
1- accidental magic:
suspension of "but Harry is a pure child with the power of love and plot" required.
accidental magic happens due to & during extreme emotions. Harry was systematically starved, slaved, scorned, bullied, beaten, and what not that means abused, his entire childhood at the Dursleys. Meanwhile he is magically powerful enough to cast a corporeal patronus of absurd power (like, 100 dementors flee from it) at 3rd year, with a remarkable lack of happy memories, and has the willpower to shrug off a death eater's imperius curse at 4th year.
The only way for the Dursleys to have survived their behavior with him would be for Harry's magic to have been sealed since they took him in. Even if that is the case, Harry still had accidental magic, particularly something as difficult as apparating, meaning that whatever block couldn't hold it all in. Which makes it implausible that the worst an abused child would have caused would be changed hair color on a merely upsetting substitute teacher. Considering Marge was as large and abusive as Vernon, had her large and violent dogs, and was not being spared accidental magic after Harry's magic had already had 2 years to stabilize with wand use and education, we can also disregard Harry having been deeply enough conditioned to subservience before his magic managed to kill them.
tl:dr the Dursleys should either have died very early, or learned against their abusiveness. plot bunny about Dursleys having died by karma early during Harry's childhood, or treating Harry as if he were the dark lord.
2- deus-ex-ward:
derived from #3. If argued that the blood wards were draining enough to prevent accidental magic within the house, then Harry should either have died (less than 2 years old when the wards begun draining), become a squib (same reason as before), or have the "magical muscle" to show for having survived it with his magic intact. Consequences: unsuited wand(s) explode while matching for a wand, at least Ollivanders wand shop would have been destroyed, if not Diagon alley as well. Harry is the magical equivalent of a high yield nuclear reactor / bomb, and as such is treated with equal care.