There's a fanfic titled 'Power Convergence'. It features a story where a character with the Rinnegan somehow ends up in the Fairy Tail world. The author does a great job of exploring how the Rinnegan abilities would be perceived in a world full of magic. It has some epic battles between the new 'hybrid' character and the powerful mages of Fairy Tail.
Well, 'Rinnegan in Fiore' is also a great one. It delves deep into the idea of what would happen if the Rinnegan was considered a form of extremely powerful and rare magic in the Fairy Tail universe. The plot thickens as different guilds either try to recruit the owner of the Rinnegan or try to eliminate the perceived threat.
Well, I've come across some. In some of these fanfictions, the characters with the Rinnegan might end up in the Fairy Tail universe and form alliances or rivalries with the Fairy Tail wizards. It often depends on the creativity of the author in mixing the two very different worlds together in a believable and engaging way.
Well, in some fanfics, they might explore the idea of Irene's backstory being intertwined with Naruto's journey. Maybe Naruto is on a quest in the Fairy Tail universe and discovers a connection between his own powers and Irene's ancient magic. It could be a story full of action and adventure, with Naruto using his ninja skills to navigate the magical world of Fairy Tail and facing challenges related to Irene's character.
A fanfic that I really liked is 'Naruto and Fairy Tail: United Worlds'. It's not just about the Sharingan but also about how the Naruto characters integrate into the Fairy Tail world. The author does a great job of mixing the two universes' rules and cultures. For example, Naruto's ninja skills blend with Fairy Tail's magic system in battles that are both creative and intense.
When writing such a fanfic, start with a strong plot. For example, you could base it on a conflict. Say, an evil force is trying to take over both the Naruto and Fairy Tail worlds, and only by combining the powers of the Rinnegan and Fairy Tail magic can it be stopped. As for the writing style, use vivid descriptions to bring the battles and magic to life. Also, don't be afraid to introduce new characters that are a blend of the two universes, like a ninja - mage hybrid.
One good weak Naruto in Fairy Tail fanfic could be 'Naruto's New Adventure in Fairy Tail'. In this fic, Naruto starts off as a rather weak character in the Fairy Tail world, having to relearn how to use his skills. It has some interesting character interactions, like when he meets Natsu and they have a friendly spar that shows Naruto's initial struggle.
I really like 'Erza's New Journey in Naruto'. In this fanfic, Erza somehow gets transported to the Naruto world. The story shows how she adapts to the new environment, with all the ninjutsu and different cultures. It's fascinating to see her interact with Naruto and his friends. Also, 'Fusion of Powers' is a good read. It's about a scenario where the powers of Naruto characters and Erza's magic start to blend, creating some unexpected and exciting situations.
One popular 'godlike naruto crossover fairy tail fanfic' is 'Naruto in Fairy Tail'. In this fanfic, Naruto's overpowered abilities from the Naruto universe are introduced into the Fairy Tail world. It creates really interesting scenarios where Naruto has to adapt to the magic - based society of Fairy Tail while still using his ninja skills.
There's a fanfic called 'Alliances Beyond Worlds'. In this, the main characters from each series form an alliance to face a common threat that endangers all three of their universes. It's really interesting to see how the different fighting styles and magic/powers interact. For instance, the Demon Slayer's breathing techniques blend with Fairy Tail's magic in unexpected ways.
One great Naruto and Fairy Tail fanfiction is 'Natsu in the Hidden Leaf'. It combines the magic of Fairy Tail with the ninja world of Naruto in an interesting way. The story follows Natsu as he somehow ends up in the Hidden Leaf Village and has to adapt to the new environment while also showing off his Fairy Tail powers.
One great 'Mata Rinnegan Naruto Fanfic' is 'The Rinnegan's Ascent'. It really delves into how Naruto might interact with the power of the Rinnegan in new and unexpected ways. The author does a wonderful job of exploring the lore and creating unique battles and character development.