One interesting plot could be Naruto gradually learning to control the power of the god sealed within him. Maybe he discovers new jutsus or abilities that are unique to the god's power. For example, he might be able to manipulate time or space in a way that no other ninja can.
Another plot could involve the reactions of the other characters in the Naruto universe. Some might fear Naruto because of the god sealed in him, while others might see him as a new hope. Sasuke could be conflicted between his rivalry with Naruto and the potential danger the god's power poses. And the Hidden Villages might try to either control Naruto or eliminate him to prevent chaos.
In many such fanfictions, it could be a variety of deities. It might be an ancient and powerful god from Naruto's world's mythology that the story's author has chosen to insert. For example, it could be a god of elements like a super - powerful fire god, which could give Naruto even more control over his existing fire - based jutsu and new, more extreme abilities related to fire.
With his enemies, it would be a whole different story. They might be more cautious about attacking Naruto. Some might even try to find a way to use the god sealed in him for their own purposes. And Naruto's relationship with the hidden villages could also change. They might see him as a potential threat or a very valuable asset.
It makes him more powerful, which could lead to overconfidence at first. But as he realizes the great responsibility that comes with the god's power, he becomes more mature. For example, he might be more cautious in battles, thinking not just about winning but also about the consequences of using the god - like abilities.
In some fanfictions of this kind, the wolf sealed in Naruto might have a past connection to a long - lost clan or an ancient evil. This could lead to Naruto uncovering secrets about the ninja world that were previously unknown. Maybe the wolf was sealed for a reason related to protecting a powerful artifact or prophecy, and Naruto now has to deal with the consequences of that.
I'm not entirely sure if there is a specific fanfiction with exactly that premise. However, given the popularity of both Naruto and the concept of sealing powerful entities in Naruto's world, it's quite possible. Fanfiction writers love to experiment with combining different fictional elements, so it wouldn't be surprising if someone has written a story where Jenova is sealed in Naruto. You can try searching on popular fanfiction websites like Fanfiction.net or Archive of Our Own to find out for sure.
Maybe Naruto's god powers allow him to travel through different dimensions at will. He could visit the Otsutsuki home planet and learn about the true origin of chakra, and then bring that knowledge back to Konoha to revolutionize ninja training. He might also encounter other god - like beings in these dimensions and have to prove himself.
Well, Naruto might become more mysterious. Since Gaster is an unknown and rather enigmatic entity, Naruto could start having strange thoughts or powers that he doesn't fully understand at first. He might seem more withdrawn as he tries to figure out what's going on inside him, and his normal cheerful and straightforward personality could be clouded by the presence of Gaster.
He could gain the power of manipulation. Gaster might give Naruto the ability to manipulate space or time on a small scale. Maybe he could create small portals or slow down time for a short period during combat.
His abilities would change in multiple ways. Firstly, his chakra control might be affected. Since Godzilla is a massive and powerful entity, it could disrupt Naruto's normal chakra flow. However, he could also learn to harness Godzilla's power within him. For example, he might be able to use Godzilla's raw strength to enhance his Sage Mode or even his Nine - Tails transformation. This could make him an even more formidable opponent. His speed could also be enhanced as Godzilla's power might give him a boost in his physical capabilities, allowing him to move faster and react quicker in battle.
In such a fanfiction, Naruto might gain some extraordinary powers related to the phoenix. For example, he could have the ability to heal quickly like the phoenix's regenerative powers. He may also be able to use fire - based attacks that are far more powerful and unique compared to his regular jutsu.