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.
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 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.
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.
I would recommend 'Naruto and Shukaku: A New Alliance'. In this fanfiction, it focuses on a scenario where Naruto and Shukaku have to team up against a new, powerful enemy. It has a lot of action scenes and also some really interesting character development for both of them.
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.
Good fanfiction in this regard also pays attention to the lore of the Naruto universe. It should be consistent with the rules about chakra, jinchuriki, and the world - building already established in the original series. If it just ignores all these elements, it won't feel like a proper 'naruto and shukaku' story.
Naruto would win. He has a lot of experience fighting powerful opponents and has developed many powerful jutsu over time. He also has the willpower and the ability to adapt in battle. Shukaku is strong, but Naruto's intelligence and his ability to think on his feet would give him the edge.
Obviously Naruto would be the main character. Shukaku itself or a representation of Shukaku's spirit could be there. Also, characters like Iruka sensei would still be around. His friends like Sasuke and Sakura would play important roles as they react to Naruto's new situation.
Well, it could be about Naruto having the powers of Shukaku in addition to his own. Maybe he has to learn to control this new power source and face new enemies who are after his unique abilities.