Well, a common plotline is Natsu having to deal with the social differences. As a girl, people might treat Natsu differently. Maybe Natsu gets underestimated in battles because of the new appearance. Also, there could be a love - interest - related plotline. A character who was just a friend before might start having different feelings towards Natsu as a girl. And Natsu might be confused about these new emotions around relationships.
One interesting plotline could be Natsu trying to adjust to the new physical form while still having the same adventurous spirit. For example, Natsu might initially struggle with wearing different types of clothes that are more suitable for a female body. Another plotline could be how Natsu's friends react. Some friends might be shocked at first, but then quickly accept and help Natsu through this strange transformation. There could also be a plotline where Natsu discovers new abilities or sensitivities that come with being in a female form.
One interesting plotline could be Bella's struggle to control her new vampire instincts while still maintaining her relationships with her human friends and family. For example, she might have a hard time being around them without revealing her new nature.
Well, there could be a plotline where Castiel in dog form gets adopted by a family. He has to balance living as a normal dog in a human household while also trying to figure out how to reverse the spell or whatever caused him to turn into a dog. This could involve him protecting the family from supernatural threats that they are unaware of, all while being a cute furry companion.
A great plotline could be the mystery behind who turned Hermione into a baby. It could be a dark wizard trying to stop her from achieving something in the future. As a baby, Hermione might start showing some unusual magical abilities that she didn't have before, which could attract the attention of both good and bad forces in the wizarding world. And her friends would be in a race against time to protect her and find a way to turn her back.
Perhaps there's a plotline where the transformation into a ferret has some unforeseen side effects. For example, Harry might gain some ferret - like abilities such as enhanced sense of smell or speed, which he then uses to his advantage in solving a mystery or escaping from a dangerous situation in Hogwarts. He could also struggle with some of the more ferret - like instincts, like being tempted to hoard shiny objects.
Natsu's friends like Gray, Erza, and Lucy are often involved. Gray might be constantly teasing Natsu about the transformation, creating some funny banter between them. Erza could be the one who tries to keep order and protect Natsu in this new form. Lucy might offer more emotional support, sharing girl - related experiences with Natsu to help her adjust.
Well, perhaps there could be a plot where Percy, as a girl, has to form new relationships. She might have a different dynamic with her male friends now that she's a girl. And there could be a story arc about her coming to terms with her new identity. Maybe she discovers new aspects of herself that were hidden when she was a boy. Also, it could be interesting if she uses her new form to her advantage in some situations, like fooling her enemies who are used to dealing with the male Percy.
One interesting plot could be Naruto, as a girl, having to deal with the different expectations of the ninja world towards females. For example, she might face challenges in being taken seriously in combat training at first. Another plot could involve Naruto's friends' reactions. Some might be really confused, while others could quickly accept and support 'her'.
Another plot could involve Harry's friends' reactions. Some might be very accepting and helpful, while others could be confused or even act differently towards 'her'. This could lead to some interesting character development and story arcs for both Harry and his friends.
In some 'izuku gets turned into a girl fanfiction', a great plot is her struggle with self - identity. She has been a boy all her life and suddenly being a girl is a huge change. She might question her place in the hero world, whether she can still be as strong and respected. And the story could explore how she overcomes this internal conflict, perhaps with the help of her friends. At the same time, her appearance change could also lead to some comical situations, like when her old friends first see her new form and their shocked reactions.
One interesting plot point could be how Hiccup adjusts to the new physical form. For example, he might struggle with the different clothing styles and social expectations for girls in his world. Another could be the reactions of his friends. Some might be shocked at first, while others could be more accepting and help him through the transition. There could also be a plot point about how this change affects his relationship with Toothless. Maybe Toothless initially doesn't recognize him and Hiccup has to find new ways to bond with his dragon.