One interesting plot could be Harry going back in time and preventing certain tragedies from happening in the wizarding world, like stopping Voldemort's rise before it really began. Another could be him changing the relationships between characters, for example, making Snape and James Potter become friends early on.
Well, in some 'Harry Potter sent back in time' fanfictions, Harry might go back to the time when the Marauders were at Hogwarts. He could then join their adventures, and perhaps use his future knowledge to help them out. He might also try to save Sirius from being wrongly imprisoned later. It's really fascinating to think about how he could impact the past and change the future in these stories.
One interesting plot twist could be that Harry goes back in time and accidentally changes the sorting of some of the characters. For example, Draco Malfoy could end up in Gryffindor instead of Slytherin, which would completely change their relationship and how events unfold in the wizarding world.
Well, in some fanfictions of this kind, Harry might face a cruel caretaker in the orphanage. But instead of being beaten down, he uses his wits and hidden magic to stand up for himself and the other kids. He could also start to learn magic on his own, using his natural instincts, which would be a really cool plot.
One interesting plot could be Harry going back in time to prevent the death of his parents. He might use his knowledge of future events to outwit Voldemort before he becomes too powerful. Another could be Harry traveling back to his first year at Hogwarts and changing how he interacted with certain characters like Snape, which could lead to a different dynamic between them throughout the series.
In this type of fanfiction, a great plot can be Naruto going back and influencing the Third Hokage's decisions. For example, he could convince the Hokage to be more open - minded about new techniques and alliances. He might also focus on improving the living conditions in the village at an earlier stage. By doing so, he could potentially change the future of the entire Hidden Leaf Village and the shinobi world in general.
One interesting plot could be that Harry Potter is sent to an alternate universe where magic is used in a completely different way. For example, instead of using wands, they use hand gestures. Another plot might be that in the alternate universe, Voldemort won in the original world, and Harry has to find a way to reverse that in this new universe. Maybe in this alternate world, the Hogwarts houses have different characteristics and he has to adapt to that new social structure as well.
One interesting plot could be Harry going back in time to prevent the death of his parents. He might use his knowledge of future events to outwit Voldemort and his Death Eaters. Another plot could be Harry going back to his first year at Hogwarts and changing the way he interacted with certain characters like Snape, which could have a huge impact on the overall story. And he could also try to change the fate of some of the minor characters who died in the original story.
In some fanfictions, Harry goes back in time and decides to train himself better. He could seek out different magical knowledge or combat skills that he didn't have the first time around, which then changes his future interactions and battles. For example, he might learn ancient spells that give him an edge against Voldemort.
One interesting plot could be time - traveling to the founders' era. The characters might witness the creation of Hogwarts and interact with the founders. They could learn the original intentions behind the house system and the hidden secrets of the castle.
One interesting plot could be a character going back in time in the Time Chamber to prevent a major tragedy that happened in the wizarding world. For example, they might try to stop the first rise of Voldemort.
One interesting plot could be Harry and Tom going back in time and changing some key events at Hogwarts. For example, they might prevent certain dark magic from being used. Another plot could involve them using their combined knowledge from different time periods to solve a mystery that has haunted the wizarding world for ages. And perhaps they form an unlikely alliance that challenges the norms of their respective eras.