Well, perhaps the female dragon has a connection to Naruto's family in some way. Maybe she was a protector of the Uzumaki clan long ago. Naruto meets her and she initially distrusts him, but as they interact, she realizes he has the same kind spirit as his ancestors. They then embark on a journey to find an ancient Uzumaki relic that was lost and is now in the hands of a powerful enemy. Along the way, Naruto learns dragon - style combat from her.
One plot idea could be that Naruto discovers a female dragon in a hidden forest. The dragon is injured and Naruto uses his healing abilities to help her. In return, the dragon offers to teach Naruto a special form of chakra control that only dragons know. Another idea is that the female dragon is being hunted by a group of rogue ninjas for her scales. Naruto decides to protect her and they form a bond during the battles against the hunters.
One idea could be that Naruto discovers a hidden land where tigers and dragons coexist. He has to learn their ways to gain a new power. Another could be a dragon and a tiger are in a feud, and Naruto has to mediate between them using his ninja skills.
One idea could be that Naruto, as a dragon, has to protect the Hidden Leaf Village from a new threat that is specifically targeting dragons. He could use his dragon abilities like flight and powerful breath attacks to fend off enemies.
Well, perhaps in the fanfiction, the female Naruto is an outcast in the village because of her dragon summoning contract. The village elders fear the power of the dragons. So, she has to train in secret with her dragon summons. They could go on adventures to different elemental lands to gain more power and knowledge. Along the way, she befriends other outcasts who also have unique abilities. And when the village is in real danger, she shows up with her dragon army to save the day.
Well, a plot could involve Naruto being cursed with a strange power that is slowly turning him into a fire - breathing dragon. He has to learn to control the Fire Dragon Roar within him to break the curse. Or, there could be a new villain in the Naruto universe who has the ability to counter the Fire Dragon Roar, and Naruto has to find a way to overcome this. Also, Naruto might travel to a land where the Fire Dragon Roar is a common form of combat, and he has to adapt and learn it quickly to prove himself.
One idea could be that Naruto's dragon summon is a powerful and ancient being. It could help Naruto in battles against extremely strong foes like Madara or Kaguya. For example, the dragon might have unique abilities like breathing fire that can melt through powerful jutsu defenses. Another plot idea is that the dragon has a connection to Naruto's Uzumaki heritage, perhaps it was once an ally of the Uzumaki clan long ago. And the dragon could also teach Naruto new and powerful techniques that are related to dragon - like chakra control or flying abilities, which would give Naruto an edge in his ninja adventures.
One plot idea could be that the main character, who has the dragon bloodline, teams up with Anko to face a new and powerful enemy in the Naruto world. This enemy could be after the power of the dragon bloodline.
Another plot idea is that the elemental dragon has a connection to Naruto's past, like it was a guardian of his clan long ago. Naruto has to learn to control it and unlock its full potential. He might go on a journey to find ancient scrolls that teach him the secrets of the dragon's power.
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 that Naruto uses the Dragon Henge to infiltrate a secret organization that has a dragon as its symbol. He could gather intelligence while in the form of a dragon.
Perhaps in the fanfiction, the dragon soal (soul) is a key to unlocking an ancient prophecy. Naruto, being the main character, has to go on a journey to understand the dragon's power and how it relates to the future of the ninja villages. He might face challenges from those who want to use the dragon's power for evil.