A 'tails born as a girl' fanfiction could focus on her fashion sense and how it reflects her personality. Maybe she creates her own unique style of clothing that combines functionality (for flying and using her tools) with a girly touch. This could be a fun way to show her creativity. Also, you could explore how she deals with the expectations of others. Some might expect her to be more delicate, while she wants to be known for her strength and smarts. This conflict could drive the story forward.
One idea could be that as a girl, Ichigo discovers new friendships in a different way. Maybe she forms a closer bond with female characters who previously saw her as a rival when she was male. Another could be that she has to deal with different expectations in the Soul Society as a female Shinigami, like different training regimens or social norms.
One idea could be that as a girl, Sasuke might face different challenges in the ninja world regarding gender expectations. For example, she could be underestimated at first but then prove herself to be just as strong as in the original story. Another plot could involve her having different relationships with the male characters, like a more sisterly bond with Naruto perhaps.
One idea could be a story where Shadow and Tails team up to save a lost ancient technology from a group of villains. They use their unique skills, with Shadow's speed and strength and Tails' intelligence and mechanical aptitude.
One interesting idea could be new jutsu created specifically for Naruto in the fanfiction. For example, a unique fire - style jutsu that combines with his wind - style Rasengan.
Another idea is to create a fanfiction where Abbadon has to team up with an unlikely ally. This could lead to some interesting character development and interactions as they work towards a common goal, perhaps saving a world from a greater threat.
One idea could be that as a girl, Harry has different social interactions at Hogwarts. For example, she might form closer friendships with female characters earlier. Maybe she would be more empathetic in certain situations compared to the male Harry in the original story.
Maybe in the fanfiction, the three - tailed beast crosses over into a modern - day human world. People initially fear it, but then they discover that it has a gentle side and is actually trying to find its way back home. It could form a bond with a group of humans who help it on its journey, leading to many adventures along the way.
Maybe a fanfiction where Knuckles has to protect Tails during a dangerous situation, like an invasion by a new enemy. This could show their friendship and how they rely on each other's strengths.
One idea could be exploring the origin of the Ten - Tails in a different light. Maybe it was created by an ancient civilization for a noble purpose that got corrupted over time. Another could be a story where a young ninja discovers a hidden power within the Ten - Tails and has to learn to control it without being consumed by its dark energy.
One idea could be that Fluttershy discovers Tails' mechanical skills and they work together to build a special sanctuary for injured animals in both their worlds. This would combine Fluttershy's love for animals and Tails' engineering prowess.