Yes, there might be. The Naruto and One - Punch Man fandoms are both large, and it's not uncommon for fans to create crossover fanfics. In such a fanfic, Naruto could be depicted as a fan of Garou for various reasons, like being impressed by his fighting style.
One idea could be a story where Garou and Metal Bat are forced to team up against a common enemy stronger than they've ever faced. They start off hating each other but gradually learn to respect each other's fighting styles.
For a good character interaction between Garou and Saitama, start with their fundamental differences. Saitama is a hero who is bored with the lack of challenge, while Garou hates heroes. Have them start with a fight, but make it a comical one where Saitama's nonchalance annoys Garou to no end. This can lead to some great dialogue exchanges where Garou tries to taunt Saitama into taking him seriously, but Saitama just doesn't care.
The plot might involve Naruto reading about Garou in some kind of multiverse scroll. Intrigued, he uses his shadow clone jutsu to search for Garou. When they meet, Naruto is all excited and asks Garou a million questions about his fighting techniques. Garou is initially annoyed but then realizes Naruto has a pure heart and they end up having adventures together.
Another option is a crossover with a post - apocalyptic world. The garou's survival instincts and combat abilities would be well - suited for this harsh environment. It could either be a lone wolf trying to survive or join a group of survivors, bringing its own set of skills and challenges to the group.
One idea could be a story where a young hero has the determination of Naruto and the combat style of Garou. He could be from a small village that's looked down upon, much like Naruto's Konoha in the beginning. He trains hard, using Naruto - like perseverance and Garou - like fighting instincts to rise through the ranks and prove himself to the world.
Writing a great 'naruto like garou fanfic' is no easy feat. You should start by deciding on the central theme. Is it about redemption like some of Garou's storylines or about achieving a great goal like Naruto? Then, think about the setting. It could be a new world that blends the fantastical elements of Naruto's world with the more gritty and urban feel of Garou's. When creating the characters, give them traits from both Naruto and Garou. For the plot, create a series of challenges that force the characters to use both Naruto - like and Garou - like skills. For instance, they might have to face a moral dilemma like Naruto and then fight their way out of it using Garou's combat skills. Also, don't forget to add some emotional depth to the story, so the readers can really connect with the characters.