In many fanfictions, Naruto is indeed presented as the Nine - Tail Fox or having a very special connection to it. This is because in the original Naruto series, Naruto has the Nine - Tail Fox sealed within him. Fanfiction writers take this concept further. They might show Naruto being able to fully control the Nine - Tail Fox's power in ways not shown in the original story, or they might explore the psychological and physical implications of being one with the Nine - Tail Fox on a deeper level. For example, some fanfictions might have Naruto transform into a more powerful and unique form that combines his own characteristics with those of the Nine - Tail Fox.
Fanfiction in this Naruto - Fairy Tail fox theme often plays with the idea of transformation. Just as in Naruto where characters can transform into more powerful forms related to the fox, in a fan - made story for this cross - over, a Fairy Tail character might gain the ability to transform into a fox - like being with Naruto - style powers. This could change their fighting style completely. Also, the relationships between characters can be re - imagined. Maybe a character from Naruto forms an unlikely alliance with a Fairy Tail mage because of their shared connection to the fox concept.
One possible plot could be that Naruto, with his fox tail which might be a sign of his special power or heritage, somehow ends up in the world of Fairy Tail where he meets Erza. They start off as strangers but gradually get to know each other through various battles and challenges. Naruto's unique abilities, including those related to his fox tail, intrigue Erza and they start to develop feelings for each other as they fight side by side against common enemies.
There could be a fanfiction where Naruto's fox tail gives him some unique abilities. For example, it might enhance his speed or agility, or it could have some sort of stealth - related power. This would make him an even more formidable ninja, and the story could revolve around his training to master these new powers.
One possible reason could be a strange side - effect of his connection with the Nine - Tails. Since he has the Nine - Tails' chakra within him, in the fanfiction world, this chakra might start to physically manifest in the form of fox ears and a tail during his time in Wave. Maybe the unique environment or a specific event in Wave triggered this abnormal transformation.
In a fanfiction, Female Naruto with fox ears and tail might have a special connection to the Nine - Tailed Fox spirit. The fox ears and tail could be a sign of a deeper bond that she has with the tailed beast. This could lead to new jutsu or abilities that are related to both her femininity and the fox - like nature. For example, she could create illusions that are fox - themed or use her tail as a weapon in a more graceful way than normal attacks.
One interesting fanfiction could be about a female Naruto who has a special bond with Kurama. In this story, her fox tail might be a symbol of her unique connection. Maybe she uses her connection with Kurama and the power of her fox tail to protect the village in a different way than the original Naruto. For example, she could have more intuitive and nature - based powers related to the fox spirit within her.
You can try Archive of Our Own (AO3). It has a large collection of Naruto fanfictions, and you might be able to find some specifically about Naruto having a fox tail by using the search function. Just type in relevant keywords like 'Naruto' and 'fox tail' and browse through the results.
One idea could be that Naruto's new fox features give him enhanced senses. He could use his improved hearing to detect hidden enemies or his sharpened sense of smell to track down missing ninjas. For example, in a mission to rescue a kidnapped villager, his new abilities help him find the secret lair of the enemy much faster than his teammates.
There's also 'Naruto: Unleashing the Fox Tail'. This one is more action - oriented. It shows Naruto using his fox - like abilities, especially his fox tails, in creative ways during battles. The story also has some cool interactions between Naruto and Kurama that add depth to their connection.