Yes, there might be. There are numerous fanfiction stories out there in the Naruto fandom, and with such an interesting concept as 'naruto is juubi x fem bijuu', it's quite possible that someone has written a story about it. You can check on popular fanfiction websites like FanFiction.net or Archive of Our Own (AO3).
We can expect a lot of creative interpretations. It might involve Naruto having unique powers and abilities due to his connection with the Juubi and the fem bijuu. There could be new storylines related to Naruto's role in the ninja world with this new form or relationship. Also, the relationship between Naruto and the fem bijuu could bring in elements of cooperation, conflict, or even romance depending on how the writer approaches it.
One possible plotline could be Naruto struggling to come to terms with his half - bijuu nature while also dealing with his relationship with the fem bijuu. Maybe there are other characters who are either afraid or in awe of his unique state, leading to various conflicts.
The power dynamics could be complex. Since Naruto is half - bijuu, he might have some powers that are a blend of human and bijuu abilities. The fem bijuu, being a full - fledged bijuu, would likely have more raw power initially. But Naruto could have the advantage of being able to think more like a human and strategize better.
The other female Bijuu are also main characters. Each of them may bring different elements to the story. They could have distinct personalities, abilities, and backstories. For example, one female Bijuu might be more calm and wise, while another could be more hot - tempered. Their interactions with Naruto and with each other are important aspects of the story.
One possible interesting plotline could be the development of Naruto's relationships with the female Kyuubi and other female Bijuu. For example, how he overcomes the initial differences and misunderstandings between them. Maybe at first, the female Kyuubi is distrustful of Naruto due to her past experiences, but as they interact more, she starts to see his true nature and they form a bond.
In fanfiction, if Naruto is half - bijuu, it could mean he has enhanced physical abilities. For example, he might have greater strength and speed like a full - bijuu. His chakra reserves could also be much larger, allowing him to perform more powerful jutsu for longer periods.
One great fem Naruto x fem Kyuubi fanfiction could be one that focuses on their unique bond. It might explore how they interact in a world where Naruto is female and the Kyuubi also takes a female form. For example, it could show them teaming up against common enemies and how their combined powers are different from the original story.
In many Naruto fanfictions, if Naruto has three bijuu, they could be the Nine - Tails (Kurama) which he already has in the original series, perhaps the Eight - Tails (Gyuki) as it has a connection with Naruto's world and Akatsuki's hunt for the bijuu. And another could be the Three - Tails (Isobu). However, it really depends on the specific plot and creative direction of the fanfiction.
It could be Shukaku. Since Shukaku was one of the first bijuu introduced in the series and has a sand - based power, it would be an interesting addition to Naruto's arsenal. Naruto's positive and energetic personality could also have an impact on Shukaku's usually grumpy and solitary nature.