One interesting Naruto Shukaku fanfiction could be about Shukaku's backstory before being sealed into Gaara. It might explore how it lived in the desert and its interactions with other beings there.
Some fanfictions might involve alternate universes where Shukaku has different powers or abilities. Maybe in one such story, Shukaku can transform into a more powerful and benevolent form and teams up with Naruto to save the ninja world from a new and greater threat.
One interesting storyline could be about the relationship between the Shukaku and Naruto evolving in a unique way. For example, the Shukaku might teach Naruto some ancient and powerful jutsu that was once known only to the tailed beasts. This could give Naruto an edge in battles and also deepen their bond.
One idea could be exploring the relationship between the Jinchuuriki and Shukaku in more depth. Maybe the Jinchuuriki tries to communicate with Shukaku in a different way than in the original series, leading to new powers or understandings. Another plot could involve the Jinchuuriki being targeted by a new group who wants to use Shukaku's power for their own evil purposes. The Jinchuuriki then has to fight not only to protect themselves but also to keep Shukaku from being misused.
A possible plot is that the female Shukaku is captured by an evil organization. Naruto, being the hero he is, sets out on a rescue mission. Along the way, he discovers more about the female Shukaku's past and her connection to the history of the ninja world. This could involve ancient secrets and prophecies related to the tailed beasts.
One idea could be that the female Shukaku has been living in hiding among the Leaf Village. Naruto discovers her secret and they form an unlikely bond as they train together to control her Shukaku powers. This bond then turns into a deep friendship that might lead to more as they face various threats to the village.
Some 'Naruto' fanfictions are really cool. For instance, the ones that give Naruto new powers. Maybe he gets a power related to space - time manipulation that he has to learn to control. This can lead to really exciting adventures and battles. Also, fanfictions that rewrite the whole story from an alternate point of view, like from the view of the Akatsuki members, can be very interesting as it shows a different side of the 'Naruto' universe.
One plot idea could be a crossover where the female Kyuubi and female Shukaku are somehow transported to the FF7 world. They could team up with the FF7 characters to fight a common enemy, perhaps a new threat created by a combination of Naruto -verse and FF7 -verse magic or technology.
The other Jinchuurikis could be potential allies. They understand the struggles and the power that comes with having a tailed beast inside them. For example, Killer Bee, who has a good relationship with his tailed beast, could share his insights on how to better co - exist with Shukaku. Tsunade might also be an ally, as she is a powerful Hokage who could offer protection and resources to the Jinchuuriki.
One idea could be that Shukaku is somehow transported into the Harry Potter universe. Maybe he ends up in the Forbidden Forest and has to navigate the magical creatures there. Another could be a story where a Hogwarts student discovers a way to summon Shukaku during a particularly difficult time at school, like when facing a powerful dark wizard. Or perhaps Shukaku's powers are combined with a Hogwarts spell to create a new form of magic.
There might be a fanfiction where Naruto is sealed by an ancient jutsu gone wrong. His friends then embark on a journey to discover the origin of the seal and how to reverse it. They might encounter various challenges and meet new characters along the way.
One interesting 'Naruto Hoshigakurei' fanfiction could be about a new character from Hoshigakurei joining the main characters on a mission. They might bring unique skills and a different cultural perspective from their village.