One sad OC (Original Character) fanfic in Fairy Tail could be about an OC who loses their magic abilities. This would be a really tragic story as in the Fairy Tail world, magic is such an important part of one's identity. The character would have to struggle with feelings of worthlessness and isolation.
One great 'Fairy Tail Laxus OC Fanfic' is 'The Lightning's New Path'. It adds an interesting original character who has a unique relationship with Laxus. The story develops the OC's backstory well and weaves it into the Fairy Tail universe in a seamless way.
Think about the themes in Fairy Tail that can be turned into a sad story for your OC. For instance, the concept of friendship. Your OC could be betrayed by a supposed friend in the guild. Develop the OC's character arc in a way that shows their downward spiral into sadness. Show their reactions, like crying alone in their room or avoiding the guild members they used to be close to.
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 great 'Fairy Tail OC Water Dragon Slayer' fanfiction is 'The Water Dragon's Heir'. It has an amazing plot where the OC, a water dragon slayer, discovers her true heritage while on a journey with the Fairy Tail guild. The character development is really well - done, and it stays true to the spirit of Fairy Tail.
One great 'Fairy Tail OC x Gray' fanfiction is 'Frozen Hearts and New Beginnings'. It has a really interesting OC who has a unique magic that clashes and then meshes well with Gray's ice - make magic. The story has a slow - burn romance that's very engaging.
One great Fairy Tail OC Femslash fanfiction is 'The Bond of Two Souls'. It focuses on two original female characters who form a deep connection. The story is well - written with great character development. Another is 'A New Chapter for Us' which has a unique plot that revolves around the relationship of the OCs in the Fairy Tail universe.
One great Fairy Tail female OC fanfiction is 'The Newcomer in Fairy Tail'. It has a well - developed female OC who joins the guild and has to prove herself. Her character arc is really engaging as she overcomes various challenges.
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.
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.