Another plotline could involve the adopted sister coming from a different village and having a hard time adjusting to life in Konoha. Naruto, having been an outcast himself, can relate to her struggles. He shows her around, introduces her to his friends, and they gradually form a strong bond as she starts to feel at home.
One possible plotline could be Naruto's overprotective behavior towards his sister in the fanfiction. He might get into fights with anyone he perceives as a threat to her. For example, if a boy shows interest in his sister, Naruto could go all out to intimidate the poor guy, creating some comical and tense situations.
A common plotline is the sister having a special power or ability that aids Naruto. For example, she might have a healing ability that helps Naruto recover from his battles faster. Another is the sister being involved in Naruto's search for Sasuke. She could be the one who tries to convince Sasuke to come back to the Leaf Village when Naruto fails at first.
One possible plotline could be Naruto forming a unique bond with Chomei. Maybe Chomei helps Naruto in a difficult battle by using its special abilities, like its ability to manipulate the nano - sized insects. This could give Naruto an edge against a powerful enemy.
One plotline could be Naruto teaching his sister ninjutsu. Since Naruto has his own unique skills like the Rasengan, he could pass on some basic forms of it to his sister. Another could be Naruto protecting his sister from the village's initial distrust, just as he faced it himself. Maybe he has to stand up to the village elders to ensure his sister gets a fair chance at becoming a ninja.
Maybe Naruto forms an army to explore a new and dangerous territory. He realizes that there are threats lurking in an uncharted land that could potentially harm the ninja world. So, he uses his charisma to assemble an army of brave and skilled ninjas. This army would be made up of different types of ninjas, like those with special bloodlines and those who are experts in stealth or combat. They would set out on an adventure, facing various challenges along the way.
The sister could have her own love story intertwined with the events of the wizarding world. She might fall in love with a Gryffindor, which would be a huge scandal in the eyes of some. This relationship could be a source of tension, not only within her family but also in the wider wizarding community. And as Severus tries to protect his sister from the dangers of the wizarding war, her relationship could add an extra layer of complexity to his already difficult situation.
One possible plotline could be Naruto unlocking the Mangekyo Sharingan through some strange and unforeseen means, perhaps a powerful jutsu backfires and gives him this new power. Then he has to struggle with controlling it while his friends are both amazed and a bit worried about this new development in him.
One possible plotline could be Naruto using the EMS and Rinnegan powers to finally bring true peace to the ninja world. He might use the enhanced visual abilities of the EMS and the god - like powers of the Rinnegan to defeat a new, extremely powerful enemy that no one else could handle.
One interesting plotline could be Naruto's newfound dragon blood gives him the ability to breathe fire. This would completely change the way he battles, adding a new and powerful offensive skill. He could use it to surprise opponents and also in combination with his shadow clone jutsu, like having clones surround an enemy and then all breathe fire at once.
One possible plotline could be Naruto struggling to control the power of the Alpha Stigma. He might initially be feared by his friends in Konoha because of its unknown nature. Another could be that enemies are attracted to the power of the Alpha Stigma within Naruto, leading to new and powerful adversaries coming after him. Maybe he has to go on a journey to learn more about the origin of the Alpha Stigma to fully master it and use it for good.