In a more complex plot, the tailed beast in Sakura could be linked to an ancient prophecy. The entire ninja world might be in danger, and only Sakura, with her unique bond to the tailed beast, can save it. Along the way, she might face challenges from other villages who want to capture the tailed beast for their own purposes. She would have to fight against powerful foes while also trying to figure out the true meaning of the prophecy and how to fulfill it.
Perhaps the tailed beast inside Sakura has a mind of its own. It could communicate with her and offer her different perspectives on the ninja world. This could lead to Sakura making choices that are different from what her friends expect. For example, she might try to broker peace with an enemy village because the tailed beast has shown her the futility of war. The story could also involve her training with Kakashi or other experienced ninjas to better understand and use the tailed beast's power.
Some Tumblr blogs dedicated to Naruto fanfiction might also have what you're looking for. There are many fanfic writers on Tumblr who create unique stories. You can search for tags related to Sakura and tailed beasts. But be aware that Tumblr's search function can be a bit tricky sometimes, so you might need to dig a little deeper.
In this fanfiction, the plot might involve Naruto being experimented on by some dark force. This experiment causes him to transform into a tailed beast in a way that's different from his normal jinchuriki forms. As he changes, he starts to view the world from a more primal perspective. He might even break away from the Hidden Leaf Village and the story could be about his journey to regain his sanity and his place among his friends and the village.
One common theme could be power struggle. Since tailed beasts are very powerful, Sakura would have to deal with the new - found power and how it affects her. Another theme might be acceptance. How does she accept being a tailed - beast - like being and how do others accept her in this new role.
One possibility is that Naruto would initially be confused and struggle to control his new form. He might accidentally cause destruction in the village as he tries to figure out his new powers. But with the help of his friends, like Sasuke and Sakura, he could start to learn to harness the tailed beast's abilities for good, perhaps even developing new jutsu.
One possible plot twist could be that Naruto's new form as a tailed beast gives him the ability to communicate with all the tailed beasts simultaneously. This could lead to him uniting them in a way that no one has ever seen before, and they might work together to bring about a new era of peace in the ninja world.
The plot could involve Dante, from his own universe, being suddenly transported to the world of the Nine - Tailed Beast. He might initially be seen as a threat, leading to battles. But then, they could discover they have a common enemy and team up. Maybe Dante's combat skills and the Nine - Tailed Beast's power could be combined in an epic showdown against a greater evil.
Well, it could be about Sakura's journey in motherhood. Maybe she faces challenges in taking care of the baby, like sleepless nights and learning how to feed properly.
One possible plot could be that Sakura somehow inherits the Sharingan. Maybe she is involved in a dangerous mission where she comes across an Uchiha survivor who, before dying, transfers their Sharingan to her. She then has to learn to control it while dealing with the prejudices and expectations that come with having such a powerful and rare ability in a world that already has certain ideas about who should possess the Sharingan.
There could be some great 'sakura is a tailed beast' fanfiction out there. One way to find them is to join relevant fan communities. On platforms like Reddit, there are sub - forums dedicated to different fanfictions. You can post a request asking for 'sakura is a tailed beast' fanfiction and the community members might be able to point you in the right direction. Also, when you do find some, look for ones that have a unique take on the idea. Maybe a fanfiction where Sakura has to control the tailed beast's power while also dealing with the normal challenges in her world.
Perhaps the 'mask beast' represents some kind of inner demon or a powerful enemy in Sakura's world. Her struggle in its grip could symbolize her battle with her own fears or a difficult situation she's facing. It could also be part of a larger story where she has to overcome this obstacle to achieve a greater goal, like saving her friends or her world.