The fanfiction might start with Ilya performing a summoning spell that she thought would bring something else, but instead, Naruto appears. Since Naruto is always eager to make friends and help others, he quickly bonds with Ilya. They could then embark on a journey to find a way to send Naruto back home. During this time, Naruto could teach Ilya about the importance of perseverance and believing in oneself, just like he learned in his own adventures in the Naruto world.
The interaction between them could be really interesting. Ilya, coming from her own magical background, would show Naruto some of her unique spells and abilities. Naruto, impressed by her magic, would then try to combine it with his ninja techniques. For example, he could use Ilya's teleportation spell in a new way during a fight. And they would also have some emotional exchanges, like when Naruto shares his story of losing Sasuke and Ilya comforts him with her own understanding of loss in her world.
Well, in such a fanfiction, Naruto might learn unique skills from the summons. For example, he could learn stealth from a cat - like summon or brute strength tactics from a bear - like one.
One possibility is that Naruto's connection with the summons would make him more in tune with nature. For example, if he was raised by toads, he might learn their unique jutsu faster and have a different approach to combat. He could also have a different view on friendship and loyalty as summons often have a strong bond with their summoners.
Perhaps in the fanfiction, the Akatsuki organization somehow gets hold of the power to summon Final Fantasy creatures. Naruto then has to figure out how they got this power and stop them. He might have to train hard to master the same summoning techniques. He could end up summoning a Shiva to counter the Akatsuki's Ifrit summon in a huge battle that shakes the very foundations of the ninja world.
The plot could be that Raven is in a dire situation in her world. She discovers an ancient spell that might be able to bring a powerful ally to her side. She decides to use it to summon Naruto. Once Naruto arrives, they face a powerful enemy that is threatening Raven's world. They combine their powers, Naruto's Rasengan and Raven's dark magic, to defeat the enemy.
It could be powerful ancient scrolls that contain lost jutsu. These scrolls might give Naruto an edge in battles against tough opponents.
A likely main summon could be Gamabunta. He's big, powerful, and has a long - standing relationship with Naruto. He could teach Naruto some really advanced water - based jutsu.
Well, one possible plot could be that the servant Naruto summons is from a future time. This servant has knowledge of events that are yet to happen in the Naruto world. Naruto then has to use this knowledge wisely while also keeping the servant's origin a secret from others who might misuse it.
The plot could start with Shirou being in a desperate situation in his own world. He discovers an ancient spell or artifact that has the power to summon a powerful ally from another dimension, which turns out to be Naruto. Naruto then helps Shirou fight against the enemies that are threatening his world. Along the way, they face challenges that require both of their skills, like Naruto using his Rasengan against magical beasts and Shirou projecting shields to protect them from enemy attacks.
He could have a dragon as a summon. A powerful and majestic dragon that can breathe fire or ice, which would give Naruto a huge advantage in battles.