Another idea is that Iruka travels to a future time. There, he sees the consequences of his current actions and decisions. This could lead to him coming back to the present with a new perspective and trying to make changes to ensure a better future for himself and those around him.
One interesting idea could be Iruka traveling back in time to his own childhood and having the chance to change certain events that shaped his future. For example, he might be able to prevent a bad accident or make a different choice in his studies.
Perhaps in some Iruka time travel fanfiction, he travels to a time before he became a teacher. He could then meet his future students as children and influence their lives in unexpected ways, like inspiring Naruto in a whole new manner long before he enters the academy.
Kakashi could also be a common character. He is Iruka's colleague and they both play important roles in Naruto's life. In time travel scenarios, Kakashi might be involved in helping Iruka adjust to the time - shifted situation or they could work together on a mission that is affected by Iruka's time travel.
One idea could be a story where Tracer accidentally travels back to the Omnic Crisis era. She could meet the younger versions of the original Overwatch founders and try to help them in ways that might change the future of Overwatch. Another could be Reinhardt going back in time to his early days as a Crusader and having to relive some of his toughest battles with the knowledge he has now.
One interesting idea could be Tsuna going back in time to prevent certain tragedies in his family's past. This would change the whole dynamic of the Vongola family in the present.
One interesting idea could be Itachi traveling back in time to prevent the Uchiha massacre. He could use his knowledge of future events to find a way to resolve the conflict between the Uchiha clan and the village without bloodshed. Another idea might be Itachi traveling forward in time to see the consequences of his actions and how his younger brother Sasuke has turned out. He could then try to guide Sasuke in a different direction from the future he witnessed.
One interesting idea could be the characters going back in time to prevent certain tragedies. For example, they might try to stop the deaths of some important characters. This could change the whole course of the story and create new relationships and plot twists.
One idea could be Atsushi traveling back to his own past to prevent certain tragedies from happening in his life. He might change the way he was treated in the orphanage or avoid some of the early hardships. Another idea is Atsushi traveling to a future where he has become a much more powerful and respected figure, and he has to learn from that future self to come back and save his present world. And a third idea could be Atsushi getting accidentally sent to a different time period in Yokohama's history and having to navigate through that era while also trying to find a way back to his own time.
In a Ninjago time travel fanfiction, the ninjas could be sent forward in time to a post - apocalyptic version of Ninjago. They would have to figure out what went wrong and then travel back to their own time to prevent it from happening. This could involve battles with future versions of their enemies who have evolved into even more dangerous foes.
One interesting idea could be changing the outcome of key battles. For example, if a character travels back in time, they might be able to prevent a certain loss in a fight, which could then change the entire course of the story. Another idea could be related to relationships. A character might go back in time to fix a broken relationship or to start a relationship earlier than it originally happened in the ff8 universe.
Perhaps they travel forward in time instead. They see a future where Hogwarts has changed drastically, with new magical technologies and different social structures. They then have to decide whether to bring some of those ideas back to their own time or leave the future as it is to avoid disrupting the timeline.
One idea could be Hiccup traveling back in time to the era when dragons first arrived in Berk. He could witness how the initial interactions between humans and dragons began and use his modern - day knowledge to try and improve relations even earlier. Another could be Toothless accidentally activating a time - travel device and taking Hiccup to a future where dragons are extinct, making them strive to find a way to prevent such a future.