Well, Minato could be one of the characters. He was Naruto's father and died when Naruto was just a baby. Reviving him would allow Naruto to finally have a proper father - son relationship. Another possibility is Neji. His death was quite tragic during the war, and his revival could bring some interesting plot developments in the fanfic, especially in terms of his relationship with Hinata and the rest of the Konoha 11.
One character that might be revived is Obito. His story was full of twists and turns. Reviving him could lead to a redemption arc where he could make up for his past mistakes. Also, the Akatsuki members like Deidara might be revived. His unique abilities could add more action and chaos to the fanfic's plot if he were brought back to life.
It could also be Makarov. As the guild master, he has a sense of responsibility towards all his guild members. He might have some secret magic or knowledge that could be used to revive Gajeel in a moment of great need for the guild.
Naruto is a likely candidate. Given his importance in the series, a plot where he is brainwashed can create a huge impact. His powerful chakra and his role as the main character mean that if he is brainwashed, it can change the entire dynamic of the story. The enemy could use his strength against his own friends and village.
Definitely Hinata. Her gentle yet strong - willed nature could be an interesting contrast when dealing with the often - mischievous yokai from Nurarihyon. Gaara too, as his own experiences with being an outcast and having a powerful force within him could have parallels in the Nurarihyon world where some yokai are feared or misunderstood. And Rock Lee, his determination and unique fighting style could bring a new dynamic to the interactions in the fanfic.
Naruto and Bart could be a likely pair. Both are mischievous in their own ways. Naruto is always getting into trouble with his pranks in the ninja academy, and Bart is constantly causing chaos in Springfield. They could get up to all sorts of antics together, like pulling pranks on the other characters in both universes.
Naruto himself is the most obvious one. Since it's a Naruto - related fanfic, he would likely be at the center of any crossovers with god - like entities. His strong will and desire to protect his village make him a prime candidate for interacting with powerful gods.
Kakashi could also be involved. Maybe he's put in a difficult position where he can't save Naruto for some reason, like being under a powerful genjutsu or being blackmailed. This would create an interesting conflict as he's Naruto's teacher and mentor.
Well, characters like Jiraiya could be really interesting in a 'naruto crossover godlike fanfic'. He has a lot of knowledge about the ninja world and different powers, so his encounter with god - like beings would be full of potential for interesting stories. Tsunade too, as a powerful Hokage, could be involved. She could represent the Naruto world's power structure when dealing with these otherworldly god - like entities. And then there's Orochimaru, who is always seeking more power, so he would be very likely to get involved in any situation where there are god - like powers to be had.
Naruto and Sasuke are very likely. Their contrasting personalities and styles make a clothes swap between them full of potential. It would be a great way to show their differences and similarities in a new light.
Naruto and Aang would be the most obvious ones. They are the main characters in their respective worlds.
Gaara could also be part of the fanfic. Since he has his own unique abilities related to sand, there could be an interesting interaction between his powers and Naruto's summoned creatures. For example, Naruto could summon a water - based creature and they could team up with Gaara to fight an enemy that is strong against both sand and water.