Well, it could be that Naruto, being neglected in the village, is noticed by Shisui. Shisui sees Naruto's potential and decides to train him in stealth and combat skills. Naruto then starts to grow stronger under Shisui's guidance, and eventually surprises everyone in the village with his newfound abilities.
Well, the plot could involve Naruto being overlooked in his own village, so he somehow ends up in the world of One Piece where Zoro takes him under his wing. Zoro might start training Naruto in his unique sword - fighting style, which Naruto could adapt to his own ninjutsu - based combat. For example, Naruto could learn to use his chakra to enhance the speed and power of sword strikes, similar to how he uses it for his shadow clones or rasengan.
In such a fanfiction, Naruto might become extremely powerful under Kakashi's training. He could learn new jutsus faster and gain better control over his chakra. Maybe he'd also develop a closer bond with Kakashi, different from his relationship with Iruka or other characters in the original story.
It could be some of the villagers who are jealous of Naruto's sudden growth under Shisui's training. They might try to undermine him or spread false rumors about him.
Well, Naruto might become more disciplined. Since Zoro is very strict in his training regime, Naruto would have to follow rules and be more punctual. He might also become more confident in a different way. Instead of relying on his usual loud - mouthed bravado, he would gain confidence from his new skills learned from Zoro. His sense of loyalty might also be enhanced, as he would respect Zoro as his teacher and protector.
One possibility in this fanfiction could be that Naruto gains new and unique combat skills. Monkey D. Dragon is known for his revolutionary ideas and powerful abilities in the 'One Piece' world. Under his training, Naruto might learn different ways of strategizing and approaching battles, perhaps incorporating some of the more unorthodox fighting styles from the 'One Piece' universe. This could lead to Naruto becoming even more formidable, not just in terms of his ninjutsu, but also in his ability to lead and inspire others in a different way, much like how Dragon has an impact on the 'One Piece' world.
In this fanfiction, Naruto's relationship with his classmates would shift. Since he's being trained intensively by Kakashi, some might be jealous of the special attention he's getting. But others might respect him more for his growth. His bond with Shikamaru could also change. Shikamaru, being perceptive, would notice Naruto's newfound confidence and skills. They might end up collaborating more in missions or battles, with Naruto taking on a more leadership role in some cases.
In this fanfiction, the dragon could also introduce Naruto to a whole new world or dimension. There, Naruto would face different challenges and enemies. The dragon's training would be specifically tailored to help Naruto survive and thrive in this new and strange environment. He might learn to fly, for instance, or communicate with other mythical creatures, which would be really exciting for the readers.
You can try some well - known fanfiction websites like FanFiction.net or Archive of Our Own (AO3). Just use the search terms 'dragon naruto neglected' on these platforms, and you should be able to find relevant stories.