One common theme is self - discovery. As fem Tsuna travels through time, she often learns more about herself, her powers, and her place in the world. Another theme is changing the past to improve the future. For example, she might go back to prevent a certain event that had negative consequences in her original timeline.
One popular fem Tsuna time travel fanfiction is 'A New Beginning for Fem Tsuna'. It takes Tsuna back in time and shows how she uses her knowledge of the future to change things. Another is 'Fem Tsuna's Time - Travel Adventure' which has an interesting plot where she travels through different time periods in the Tsunaverse and meets various characters in unexpected ways.
Reborn is often involved. Since he is Tsuna's mentor, he could play a crucial role in guiding Tsuna during his time - traveling adventures. Maybe he has some knowledge about time travel that he imparts to Tsuna.
Fem Tsuna might try to find distractions. She could focus on her hobbies or things she was good at before the abandonment. For example, if she was good at martial arts, she could train even harder to take her mind off the pain. And in the long run, this could also make her more confident and self - reliant. She may also start to write in a journal, documenting her feelings and thoughts. This can be a therapeutic way for her to deal with the abandonment and keep track of her growth during this difficult time.
Fem Tsuna could use her pain as fuel. She starts to practice her skills more vigorously. She might think that if her guardians don't want her, she'll become so strong that they'll regret their decision. So she spends her days training, getting better at combat or whatever abilities she has in the fanfiction.
One possible scenario in a fanfiction of Fem Tsuna being betrayed could be that her closest friends turn against her because of a misunderstanding. Maybe there was some false information spread about her having some ulterior motives in the mafia world she's involved in. So, her friends, who used to trust her completely, start to distance themselves and even plot against her.
One interesting idea could be Tsuna going back in time to prevent certain tragedies in his family's past. This would change the whole dynamic of the Vongola family in the present.
One common theme is self - discovery. Since fem Tsuna is often in a different or new situation in crossovers, she has to figure out who she is in this new context. For example, in a crossover with a fantasy world, she might discover new powers or abilities that make her see herself in a new light.
Another theme is isolation. After being betrayed, Fem Tsuna often finds herself alone. She might be shunned by her community or family. This isolation can force her to rely only on herself and discover inner strength she didn't know she had. For instance, she could be forced to fend for herself in a dangerous situation without any allies.
One common theme is self - discovery. Since Tsuna is often female in these fanfictions, she has to discover her new identity and powers in the supernatural world. For example, she might find out she can control certain elements or has special abilities related to the supernatural.