One possible plotline could be that Naruto uses his newfound ability to go back in time to prevent some of the tragedies that occurred in the past related to the Bijuu. For example, he might try to stop the initial capture and sealing of the Bijuu into different vessels, which could change the entire history of the ninja world. Another could be that the Bijuu themselves, with Naruto's help, go back to a time when they were free and try to establish a new world order where they are not feared and hunted.
Well, perhaps Naruto and the Bijuu go back in time to the era when the ninja clans were first forming. They could then use their knowledge and power to bring about peace much earlier. The Bijuu might teach the clans about chakra control and the importance of coexistence. Naruto could also use his skills to prevent the formation of some of the more war - hungry clans. This would completely change the history of the shinobi world, and might lead to a more harmonious future in the present day that Naruto originally came from.
A plotline could be that Naruto and the Bijuu go back to a time when the Sage of Six Paths was still alive. They could work with him to better distribute the Bijuu's power in a more balanced way. This might prevent the power struggles that have been going on for centuries. Maybe Naruto would learn new jutsu from the Sage, and the Bijuu would have a chance to exist in a more natural state. It would be a chance for them to rewrite the history of the ninja world from a very early stage.
A possible plotline is that they go back in time and get involved in an ancient Jedi - Sith war. They could use their knowledge from the future to tip the balance in the Jedi's favor. They might also meet their ancestors or past Jedi heroes and learn from them, which in turn helps them in their fight against the dark side in their own time.
If Naruto and the Bijuu go back in time, Naruto's relationship with Madara could be completely transformed. Instead of being enemies in the future timeline, Naruto could try to understand Madara's motives from the start and perhaps prevent him from going down the dark path. The Bijuu, on the other hand, might have a different relationship with the Uchiha clan in general. They could offer their power to the Uchiha in a more positive way, rather than being something the Uchiha might try to control in the future.
They might go back in time and accidentally change something that has a huge ripple effect on the future. So then they have to scramble to fix it before they return to their own time. They could also go back in time to learn some long - lost magic from an ancient wizard or witch and bring that knowledge back to their time to defeat a new dark force.
One possible plotline could be Naruto struggling to come to terms with his half - bijuu nature while also dealing with his relationship with the fem bijuu. Maybe there are other characters who are either afraid or in awe of his unique state, leading to various conflicts.
One possible plotline could be Naruto using his old and experienced self to prevent past tragedies. For example, he might stop the Uchiha massacre. He could use his knowledge of jutsu and his understanding of people to change the course of history and bring about a more peaceful future from the start.
One possible plotline could be Naruto using his newfound time - traveling ability to prevent some of the major tragedies in the past. For example, he might try to stop the Uchiha massacre. He could also use his knowledge from the future to help his younger self become stronger faster, perhaps by teaching him some advanced jutsu he learned later in life.
A plot twist could be that the bijuu themselves have a collective consciousness that Naruto doesn't expect when he absorbs them. This consciousness could start to influence Naruto's actions during his time travels. For instance, they might guide him towards certain events or people that they believe are important for their own reasons. Maybe they want to correct some past wrongs in the ninja world that were related to their existence. This would add an interesting layer to the story as Naruto has to deal with not only the power of the bijuu but also their will.
One possible plotline could be that Noctis goes back in time to prevent the fall of his kingdom. He could use his knowledge of the future to stop the events that led to its destruction. For example, he might prevent the betrayal of a key ally or stop the spread of a deadly plague that weakened the kingdom. Another plotline could be that Noctis goes back to a time when his father was still alive. He could then learn more about his father's rule and gain valuable advice on how to be a better king. Or perhaps he goes back in time to change a personal decision that had far - reaching consequences, like a choice he made about a relationship that affected his leadership later on.
Maybe Team 7 travels back in time to a period when a powerful and evil force first emerged. They then try to stop this force from growing in the first place. Along the way, they face challenges like not being recognized by the people of that time, and having to adapt to the older ways of doing things in the ninja world. They might also encounter versions of their own families or friends in the past and have to deal with the emotional turmoil of seeing them but not being able to fully interact as they are from different times.
Well, they could go back in time and end up interfering with their own past selves. This could create all sorts of chaos, like a time paradox. Maybe Naruto as he is in the present time meets his younger self and has to convince the younger Naruto to trust him. Or Sakura could use her medical skills to heal someone in the past who was important to their development. And Sasuke might use his new skills to take on enemies in the past that were too strong for them at that time.