Well, One Punch Man fanfiction can be really interesting. Some fanfictions might explore the backstories of the characters in more depth. For example, they could expand on Saitama's life before he became so overpowered. It's fascinating to see different interpretations of the characters' personalities and relationships. Some fanfictions might also introduce new villains or scenarios that the original manga or anime didn't cover, which can add a fresh perspective to the One Punch Man universe.
Yes, there likely is. The Naruto and One Punch Man fandoms are both quite large, and it's common for fans to create crossover fanfictions. These crossovers can be really interesting as they combine the unique elements of both universes, like Naruto's ninja skills with Saitama's one - punch power.
I'm quite sure there exists a 'Naruto is One Punch Man' fanfic. The world of fanfiction is vast and full of all kinds of creative crossovers. Writers might be intrigued by the idea of bringing Naruto's ninja skills and the unique world of One Punch Man together. For example, how would Naruto react to the overpowered villains in One Punch Man's world? And how would Saitama view Naruto's determination to protect his village? These are the kind of things that could be explored in such a fanfic.
Another idea is that Naruto, curious about other powerful beings, uses a jutsu to travel to the One Punch Man universe. There, he would be amazed by Saitama's strength. Naruto could try to learn from Saitama how to be so effortlessly strong, but Saitama would probably just shrug it off and say there's no special trick. They could team up to fight some of the monsters in Saitama's world, with Naruto using his ninjutsu and Saitama just punching things away.
The villains would have diverse reactions too. Garou might see the fanfic as a source of inspiration for his own 'evil' plans. He might think that some of the ideas in the fanfic could make him an even more formidable foe. However, if the fanfic makes him look like a complete fool, he'd be enraged. Deep Sea King would be confused by the fanfic, not really understanding the concepts that are different from his simple view of the world. But he might also be intrigued by the new versions of himself presented in the fanfic.
When it comes to a fanfiction about Saitama's training days, it has the potential to be really engaging. We could see the evolution of his training methods, perhaps from simple exercises to more complex and extreme ones. It might also explore his interactions with the people around him during that time, if there were any. For example, did he have any mentors or friends who supported or doubted him? This kind of fanfiction can add a whole new layer to Saitama's character and make us appreciate his journey to becoming One Punch Man even more.
When it comes to Genos' abilities, the Avengers would be intrigued. Genos' ability to fire intense energy blasts could be a great asset in battles. Hawkeye might be thinking about how Genos could provide cover fire or take out tough enemies from a distance. But the Avengers would also be a bit worried about Genos' lack of emotional control at times. In his pursuit of power and revenge, he can be a bit reckless. The Avengers would need to work with him to make sure he doesn't go overboard. Also, Genos' loyalty to Saitama would be something they would need to understand, as it might influence his decisions within the team.
I really like 'A Punch in the Ninja World'. This fanfic has Saitama accidentally getting transported to Konoha. What makes it interesting is how the Naruto characters react to his non -chalant attitude towards their powerful jutsus. It's a short but engaging read that gives a fresh perspective on both universes.
One good One Punch Man Naruto fanfic is 'The Unlikely Alliance'. It combines the unique humor of One Punch Man with the rich ninja world of Naruto. In this fanfic, Saitama somehow ends up in the Naruto universe and his nonchalant attitude towards the powerful ninja is quite hilarious. He also teams up with Naruto at some point and they face off against some new and interesting villains created by the author's imagination.