Well, it could be that DIO imparts his unorthodox and powerful combat skills to Naruto. Maybe Naruto learns DIO's time - stopping ability in some unique way, which gives him an edge in battles against tough opponents in the Naruto universe. And he might also pick up DIO's menacing charisma, making him a more intimidating presence on the battlefield.
If trained by DIO, Naruto's character would likely change in several ways. Firstly, he might become more self - centered. DIO is all about self - preservation and power, and some of that could rub off on Naruto. However, he would still have his core values. His sense of justice might get distorted a bit as DIO's methods are often amoral. But on the positive side, he could become more confident and fearless in the face of stronger opponents, as DIO's training would surely toughen him up both physically and mentally.
In a 'Naruto trained by ANBU' fanfic, the plot could involve Naruto being secretly taken under the wing of ANBU members. They might train him in stealth and more lethal forms of combat. This could lead to Naruto having a different fighting style compared to canon, and he might face different challenges as he grows stronger. For example, he could be involved in more covert missions early on and develop a reputation among the ANBU ranks.
Well, it could start with Naruto being sent on a special mission where he encounters Sasori. Sasori, seeing potential in Naruto, decides to train him. The training would likely be tough as Sasori is a strict teacher. Naruto would have to adapt to Sasori's methods. He might learn how to control multiple puppets at once, and this new skill could help him in battles against stronger opponents in the future. For example, when facing Akatsuki members or other powerful foes.
In a fanfic where Naruto is trained by Zetsu, the story could take an interesting turn. Zetsu has knowledge of the Akatsuki and their secrets. Naruto could learn about the organization from the inside out. This knowledge could help him in his quest to bring peace. He might also gain some physical enhancements. Zetsu is quite durable in his own way, and Naruto could inherit some of that sturdiness. This would make him an even more formidable opponent in battles against strong foes like Pain or Madara.
Well, it could be that Itachi trains Naruto to better control his chakra. Maybe Itachi sees potential in Naruto to bring peace to the ninja world and decides to pass on his unique skills like the Sharingan's insights on combat.
In a 'naruto trained by ruby' fanfic, perhaps Ruby could introduce Naruto to some unique combat styles. Maybe Ruby has her own set of skills like some kind of magic or special weapon techniques. She could teach Naruto how to combine his chakra with these new elements. For example, if Ruby has some sort of elemental magic, Naruto could learn to infuse his Rasengan with that magic for a more powerful attack.
A 'naruto trained by orochimaru fanfic' might have Naruto delving deeper into the secrets of the Sharingan. Orochimaru has always been interested in the Uchiha's power. So Naruto, under his training, could be exposed to knowledge about the Sharingan and its potential. This might lead to some interesting power - ups for Naruto, but also put him in the crosshairs of other powerful ninja who are also interested in the Sharingan's secrets.
In a 'naruto trained by selphe fanfic', perhaps Selphe comes from a different ninja clan with ancient techniques. She could teach Naruto how to combine his existing Rasengan technique with her clan's special chakra manipulation. This would make Naruto's attacks even more powerful and unpredictable. Also, Selphe might train Naruto in mental discipline, which would help him better handle the stress of battles and his role as a future Hokage.
Well, it could be about Naruto learning unique combat techniques directly from the Kyuubi. The Kyuubi, being a powerful and ancient entity, might teach Naruto some forgotten or forbidden jutsu. This would set Naruto apart from his original training path in the canon series. Maybe he'd learn how to use the Kyuubi's chakra in a more controlled and strategic way, like creating chakra shields or new types of elemental attacks.
Well, it could be that Naruto gets super powerful training from each of the Sannin. Jiraiya might teach him more advanced toad jutsus and how to better control his chakra. Tsunade could train him in medical ninjutsu and physical combat skills. Orochimaru, even though he's a bit of a dark character, could show Naruto some really unique and forbidden jutsus that Naruto has to learn to resist the dark side of. And all this special training could make Naruto a much more formidable shinobi in the fanfic.