One common theme is the characters from Fairytail being involved in gaming - like scenarios. For example, they might enter a virtual world similar to the ones in modern games. Another theme could be the use of magic in a gaming context, like leveling up magic skills as if they were game levels.
One common theme is identity. Since the characters are genderbent, they often have to re - evaluate who they are in the context of the Fairy Tail world. Another theme is power dynamics. The gamer aspect can introduce new power levels and abilities, which can change how characters interact. For example, a genderbent Erza might have different gaming - inspired powers that affect her standing in the guild.
One popular theme is the power - up of characters. Fans like to write about how their favorite Fairy Tail characters gain new and amazing powers. Another common theme is romance. Pairing up different characters in the series in romantic relationships is quite popular.
Obviously, Natsu could be one of the main characters. He could befriend the gamer and be intrigued by his strange powers. Among the female characters, Lucy would be a great choice. Her celestial spirit magic and her kind - hearted nature would make her an interesting part of the harem. Also, Erza with her strong and strict personality would add a lot of drama to the harem dynamic. Maybe Gray could also be involved as a rival to the gamer in some ways, especially when it comes to the attention of the female characters.
Another place to find gamer - related Fairytail fanfiction is on Reddit. There are subreddits dedicated to Fairytail where fans often share their own fan - created stories. You might also find some in gaming - focused subreddits where fans of both the game and the anime cross - post their works. Additionally, some Discord servers related to Fairytail or gaming in general may have channels for fanfiction sharing.
One popular 'genderbent gamer fairytail fanfiction' is 'Gamer Girl in Fairy Tail'. It's a really interesting take where the characters' genders are swapped and they have gamer - like abilities in the Fairy Tail world. Another one could be 'Genderbent Fairy Tail: The Gamer's Adventure' which often has unique plot twists based on the genderbent concept.
Another element is the integration of Fairy Tail's magic system with the gamer mechanics. So the protagonist might use his gamer knowledge to better understand and manipulate the magic in the Fairy Tail world, like figuring out how to upgrade magic spells in a way similar to upgrading in a game.
One idea could be a gamer who gets sucked into the Fairytail world and starts to form a harem among the female characters. For example, he could use his gaming skills to impress them during battles. Maybe he masters a unique magic that no one in Fairytail has seen before, which draws the attention of Erza, Lucy, and other female mages. Another plot could be that he has to complete a series of in - game - like quests in the Fairytail world to win the hearts of the harem members. He might have to defeat a powerful dark guild while also dealing with the romantic interests of the girls.
You can try websites like Fanfiction.net or Archive of Our Own. They have a large collection of Fairy Tail fanfictions. Just search for 'Fairy Tail' in the search bar and browse through the results. There are often filters you can use to sort by popularity, rating, etc.
You could have an OC who is a gamer in the real world but gets transported into the Fairytail universe. At first, they struggle to adapt but then realize that their knowledge of games can help them understand the magic system better. For instance, they might compare the different types of magic to character classes in RPGs and use this knowledge to develop their own unique magic skills.