One idea could be that the Avengers go back in time to stop Thanos from ever getting the Infinity Stones in the first place. They might have to deal with different versions of themselves and the challenges of changing the past without ruining the future.
Well, in some fanfictions, the time travel might go wrong in a way that it starts to merge different timelines. So the Avengers not only have to deal with Thanos but also with the chaos of colliding timelines. For example, characters from different points in time start interacting in strange ways, like an older version of Iron Man meeting his younger self. This can lead to a lot of interesting character development and conflict resolution.
Well, perhaps the kids travel to a time when the Avengers were just being formed. They meet the younger versions of their heroes and end up having to help them in a mission that was previously unrecorded. This would add a new layer to the Avengers' backstory and give the kids a chance to prove themselves. They could also learn valuable lessons from the early Avengers about teamwork and sacrifice.
A third plot could involve her time traveling to save a member of the Avengers who was crucial to the team but died in her future. She has to figure out how to blend in with the past timeline, deal with the Avengers not believing her at first, and then work together to stop the threat that originally killed that member.
One idea could be that the next - generation Avengers accidentally travel back in time and interfere with a key event in the original Avengers' history. This causes a ripple effect that changes the present in unexpected ways. For example, they might prevent Tony Stark from creating the first Iron Man suit, leading to a world where technology has developed differently. They then have to figure out how to fix the timeline while also dealing with the different threats in this new reality.
One idea could be Goten traveling back to the Saiyan - Saiyan war era. He could end up changing some small events that have big impacts on the future, like uniting some Saiyan clans earlier. This would create a whole new timeline where relationships between characters are different.
Maybe a character travels forward in time and sees a dystopian version of the ACOTAR world. They then have to go back and try to prevent the events that led to that future. They could face many challenges along the way, like not being believed or having to work against powerful forces who benefit from the future they saw. It would be a race against time to save their world.
A possible plot for 'Haikyuu time travel fanfiction' is that Tsukishima travels back to his childhood when he first started to dislike volleyball. He could then understand why he developed that negative feeling and change his attitude from the start. This would lead to a much stronger Tsukishima in the present day. Another idea is that a team manager travels back in time to recruit a different set of players for the team, creating a completely different team dynamic. Maybe they could even bring back an old - school player who had unique skills that could revolutionize the team's playing style.
One idea could be a modern-day character traveling back in time to the Hakuoki era and getting involved in the political intrigue. They could use their modern knowledge to try and change the course of events. Another plot could involve a character from the Hakuoki world traveling to the future and being shocked by the technological advancements. Maybe they struggle to adapt to the new world but also find new ways to bring back knowledge to their own time.
Perhaps Rex travels to a time where dinosaurs and humans co - exist. He has to figure out how this is possible and if it's a threat to the future. Or he could go back to the time of the Renaissance and become an apprentice to a famous artist, using his modern perspective to influence the art world in ways that have a ripple effect through time.
One idea could be that Tony Stark travels back in time to prevent the creation of certain dangerous technologies that later cause chaos in his timeline. He could use his genius to subtly alter the course of scientific development.