Perhaps a story where Naruto's fire powers are not fully under his control at the start. He accidentally sets things on fire and has to go on a journey to learn how to master them. Along the way, he meets an old sage who teaches him unique techniques related to his fire powers.
A really interesting storyline could be that Naruto's fire powers are a result of a long - forgotten bloodline limit. As he explores this new aspect of himself, he uncovers secrets about his family's past. He then uses his fire powers not just for fighting, but also to heal emotional wounds within his family and the village.
One exciting storyline could be Naruto using his cosmic powers to travel across different dimensions to find a way to save the Ninja World from a new, otherworldly threat. He might encounter strange beings and have to learn to control his new powers in unfamiliar environments.
In Naruto fanfiction, some new powers could be the ability to manipulate time on a small scale. For example, a character might be able to slow down time for a short period during a fight, giving them an edge. Another new power could be the power to control the elements in ways not seen in the original series, like combining lightning and water to create a unique and powerful attack.
His hidden powers might be the ability to control all five basic nature types without any training. In the original story, Naruto had to work hard to master different nature types. But in a fanfiction, it could be that he has this innate ability which was hidden all along. This would make him extremely powerful and feared by his enemies.
One possible storyline could be a ronin Naruto having to prove himself in the Chunin Exam despite not being part of a regular ninja village. He might face discrimination from some of the other participants who view him as an outsider. Another could be Naruto using his unique experiences as a ronin to develop new and unexpected ninja techniques during the exam.
One interesting story could be about the origin of Naruto's ability to summon demons. In the fanfiction, it could be revealed that it was a long - lost bloodline ability that was sealed away for generations. As Naruto discovers this, he has to deal with the fact that there are those in the ninja world who want to use this power for evil. He then has to protect this secret and use his newfound ability to summon demons to stop those who would misuse it, all while trying to understand the true nature of his connection to the demon world.
A possible storyline is that Naruto is transported to a parallel dimension where all ninjas have elemental powers from birth. There, he is initially at a disadvantage because he doesn't know how to use his new - found fire control. But with the help of some friendly locals, he starts to master it and eventually uses it to fight against an evil dictator in that dimension who is trying to take over all the ninja clans. Another storyline could be that Naruto's fire control is tied to his emotions. So, when he gets angry, the fire becomes uncontrollable. He has to learn emotional control along with mastering the power to use it effectively in battle and in his daily ninja life.
One interesting storyline could be Naruto gaining the power of time manipulation. He could use it to go back and prevent some of the tragedies in the Naruto universe, like the death of his parents. This would change the entire course of the story and lead to new alliances and conflicts.
One could be Ash getting transported to a parallel Pokemon world where the rules are different. For example, Pokemon types could be combined in new ways, like a Fire - Grass type. Another storyline could be Ash being a Pokemon himself and experiencing the world from their perspective. He could struggle to communicate with humans and learn about the bond that Pokemon share with their trainers in a whole new way.
One great storyline could be Naruto exploring new fire - based jutsu. He might discover an ancient scroll that contains a powerful fire jutsu and has to go on a journey to master it. Along the way, he could face challenges from other ninja clans who also want the power. Another could be Naruto teaching his fire - based skills to the new generation of Konoha ninja, like how he imparts his knowledge and the unique ways he has developed to control and enhance fire techniques.
One possible storyline could be Naruto somehow getting his hands on a Murcielago (assuming it's a vehicle or some sort of powerful object in this fanfic). He might use it to gain an edge in his ninja battles, perhaps modifying it with his ninja skills. For example, he could add some chakra - powered enhancements to its speed or defense capabilities.