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.
One interesting plot could be that Naruto and his friends somehow get transported to the world of Final Fantasy 15. Naruto's ninja skills would be a huge asset in the new world. He could team up with Noctis and his crew to fight against a common enemy, like a powerful daemon that is causing chaos in both their worlds combined. Maybe Naruto could teach Noctis some of his chakra control techniques in exchange for learning some of the magic from Final Fantasy 15.
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.
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.
One possible plot could be that Naruto is somehow transported to the world of Final Fantasy IV. He teams up with Cecil and the others. Naruto's unique ninja skills could be used to help in battles against the various foes in FFIV's world, like the Golbez's minions. His rasengan could be a powerful new attack for the group.
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.
Well, it could be about Naruto characters getting sucked into the world of Final Fantasy 8. Maybe Naruto could team up with Squall. They'd fight some of the FF8 monsters together, and Naruto could use his jutsus while Squall uses his gunblade. It'd be a really cool mix of the two universes.
Naruto, being his curious and friendly self, would probably be excited to meet the Final Fantasy summons. He might try to befriend them immediately. For example, if he summoned a Cactuar, he would likely be amused by its appearance and try to communicate with it. Sasuke, on the other hand, would be more cautious and see the summons as tools for power. He would study them to figure out how to use them to his advantage in his quest for revenge.
One idea could be a young Naruto discovers an ancient scroll that allows him to summon dragons instead of toads. He then has to train with these dragons to master new jutsus. Another could be that the dragon summons are from a different dimension and bring with them a new type of chakra that Naruto has to learn to control.
One idea could be Naruto discovers a new summon that has a special connection to lemons. Maybe the summon can use lemon - scented jutsu or has a power that is enhanced by lemons. Another could be Naruto's summons get into a comical situation involving lemons, like a race to find the biggest lemon in the forest.
Another plot could revolve around the relationships between the existing legendary summons. Maybe there's a power struggle among them, and Naruto has to step in and mediate. He could learn about their ancient rivalries and use his skills to bring them together to face a common foe like a powerful, ancient evil that has been awakened.