After Harry kills Voldemort in the graveyard in the fanfiction, the magical balance might shift. With Voldemort gone, some of the dark magic that was prevalent might start to fade away. The Hogwarts School of Witchcraft and Wizardry could see a new golden age. New spells and magical theories might be explored as the fear of Voldemort no longer holds back the wizarding scholars. Harry himself might start to travel around the world to spread the news of Voldemort's defeat and also to learn more about different types of magic. His friends would also have new opportunities, like Hermione might be able to further her studies without the constant threat of Voldemort and Ron could finally relax and enjoy a more peaceful life at the Burrow.
The wizarding world would likely be in a state of shock and then celebration. People would start to see Azkaban in a new light, perhaps no longer as just a place of horror but also as the site where the great evil was finally vanquished.
Maybe Harry uses some powerful and unexpected spells. For example, he could combine the Patronus Charm with a blasting spell. The Patronus might distract Voldemort while the blasting spell hits him hard.
There are indeed some. One reason for the existence of such fanfics could be the desire of fans to see a different outcome earlier in the story. For example, in some of these fanfics, Harry might use his connection with Voldemort in a more aggressive way to end the Dark Lord quickly. It gives a fresh perspective on the whole Harry Potter universe and can be really interesting to read.
One popular 'Harry kills Voldemort' fanfic might be the one where Harry uses a unique spell combination that he discovers in an ancient magic book hidden in Hogwarts. This spell gives him an edge over Voldemort's dark magic.
Yes, there might be such fanfictions out there. Fanfiction writers often explore alternative storylines, and the idea of Pettigrew turning on Voldemort and killing him is an interesting and unexpected twist. It could involve Pettigrew having a change of heart due to some complex reasons, like realizing the true evil of Voldemort's ways or having a personal vendetta against him that overrides his loyalty.
Well, in some fanfictions, Harry might use some hidden magic he discovers in Azkaban. Maybe he finds a way to turn the Dementors' power against Voldemort. Since Dementors can suck out a person's soul, Harry could somehow direct them towards Voldemort, weakening him enough to deliver the final blow.
Harry might use his wits and the environment around him while in captivity. For example, if he's held in a place with magical artifacts, he could use them to his advantage. He could break the chains that bind him with a spell - enhanced object and then make his way to Voldemort and defeat him.
It's possible that there's a hidden stash of Muggle items in Hogwarts, and Harry stumbles upon it. He discovers the gun there, realizes it could be a powerful weapon against Voldemort, and decides to use it.
One popular theme is the aftermath of Voldemort's death. How does the wizarding world change? Does Harry become a sort of dictator - like figure because of his power? Another theme is the emotional journey of Harry. Killing Voldemort might not be as straightforward as it seems in terms of his mental state. He could be haunted by the act or feel a sense of loss even though Voldemort was evil. Also, the theme of redemption is common. Maybe some of Voldemort's followers are given a chance to redeem themselves in the wake of his death.