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.
One of the most interesting demons could be a shape - shifting demon. This demon could change its form to deceive enemies or help Naruto in stealth missions. For example, it could transform into an exact replica of an enemy ninja to gather information. Another interesting demon might be a demon with the power of time manipulation. Naruto could use this demon's power to go back in time and prevent certain disasters from happening in the ninja world, like the attack on the Hidden Leaf Village by Pain.
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 storyline could be a young ninja who discovers a rare and powerful insect summon. For example, they might find a group of glowing beetles that can create illusions. The ninja then has to learn how to control and use these beetles in battles against other powerful foes in the Naruto universe.
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.
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.
In fanfiction, Naruto's unique summon contract could involve summoning mythical or extinct creatures. For example, he might be able to summon a phoenix, which could give him the ability to fly and use fire - based attacks that are much more powerful than normal. This would make his battles more interesting and unpredictable.
He could summon different kinds of tigers. Maybe there are snow tigers for cold environments. These tigers would be white - furred and well - adapted to snowy areas. They could be used in missions in the Land of Snow.
One possible storyline could be that Naruto's black hair is a sign of a hidden power. Maybe his family had a secret bloodline that was suppressed, and the black hair is the physical manifestation of it starting to emerge. This could lead to new jutsus and abilities that no one has seen before.
One unique aspect is the size difference. Elephants are much larger than the toads Naruto usually summons. This can lead to different battle strategies and more destruction in the fight scenes. For example, an elephant could simply trample over enemy fortifications.
One unique storyline could be a samurai Naruto who has to protect a small village from a powerful warlord. He might use his ninja skills in a samurai - like way, like using his shadow clone jutsu to create decoys while he attacks the enemy head - on with his sword. Another could be Naruto being trained by a legendary samurai master, learning ancient samurai techniques that he combines with his own chakra powers.