A possible plot in the Harry Potter Teddy time travel fanfiction could be Teddy going back to the time of the founders of Hogwarts. He could be a sort of mediator between the four founders, especially if there were some disputes or misunderstandings that led to future problems in Hogwarts. Teddy could use his knowledge from the future to try and smooth things over. This would not only change the history of Hogwarts but also have a big impact on the future wizarding world he comes from.
A great plot might be that Teddy time travels to a time when Harry was a child living with the Dursleys. Teddy could try to secretly protect Harry from some of the bullying and neglect he endured. Or perhaps Harry and Teddy travel to a time long before Hogwarts was founded to learn about the origins of magic in the wizarding world, and they bring that knowledge back to their own time to help improve modern magic.
They could time - travel to a time in Hogwarts' history when a great mystery was unsolved. Harry and Teddy could work together to figure out what really happened. For example, they might explore the mystery of the Chamber of Secrets long before Harry's own encounter with it. Teddy's inquisitive nature and Harry's experience could lead them to some amazing discoveries.
A third idea might be that both Harry and Teddy accidentally travel to a time in the past where a great magical event took place, like the founding of Hogwarts. They have to figure out how to get back to their own time while also trying not to disrupt the events that are crucial to the wizarding world's history. They might even learn some long - lost spells or magical knowledge during their time there.
One idea could be Teddy time - traveling back to the time when Harry's parents were alive. He could try to prevent their deaths, which would create a whole new timeline. Harry would then have a very different life, perhaps growing up with his parents and without the burden of being 'the boy who lived'.
One plot idea could be that Hermione and baby Teddy travel back to the time of the founders of Hogwarts. There, Hermione uses her knowledge to help the founders with some magical problems they are facing, while Teddy, being a metamorphmagus, unknowingly reveals some future magical abilities to the wizards of that time, causing a stir. Another idea is that they travel to a time during Voldemort's first rise to power. Hermione tries to find a way to stop him earlier, with Teddy's unique abilities helping them to blend in and gather information. For example, Teddy could change his appearance to look like a Death Eater's child to get close to their secrets.
One idea could be a character going back in time to prevent a major dark wizard event that was overlooked in the original series. For example, they might try to stop the initial rise of Voldemort before he became so powerful.
Well, perhaps Harry travels back in time to the very beginning of the wizarding world. He discovers secrets about magic that have been long forgotten. He then uses this knowledge to make the wizarding world more inclusive and less divided by blood purity. Or he could time - travel during his own time period, like going back to his first year at Hogwarts over and over again to change small things that have big consequences in the future, like making sure Neville is more confident from the start.
Another plot could be that they travel back to the time when the Chamber of Secrets was first opened. Ginny, having been possessed by Tom Riddle in her own time, could use her knowledge to stop the young Voldemort from causing so much harm. Harry could also help by using his skills and knowledge of magic from his own time to combat the basilisk and keep students safe.
Well, a plot could be that a character from the future, like a descendant of Harry Potter, travels back in time to the time of the Triwizard Tournament. This character could have some knowledge of future threats and tries to prevent certain events during the tournament that could lead to greater disasters in the future. They might try to stop Voldemort's minions from using the tournament as a cover to carry out their evil plans. They could also try to make sure that Cedric Diggory doesn't die, which would have a huge impact on the wizarding community as he was a very popular and promising young wizard.
One idea could be Harry traveling back to the time of the founders of Hogwarts. He could interact with Godric Gryffindor, learn from him, and maybe even influence the way the houses are initially set up. Another plot could involve Harry going back to the time when Voldemort was a student at Hogwarts. He could try to understand what made Voldemort turn so evil and perhaps prevent some of the early events that led to his dark path.