A time - travel plot in a Precure All Stars fanfic could be really cool. Maybe the Precure travel back in time to the origin of their powers and have to make sure that the events that led to their powers being created happen correctly. It could involve meeting their predecessors and learning about the true nature of their powers.
One interesting Precure All Stars fanfiction could be about all the Precure characters from different series coming together to face a super - powerful villain that was created by combining the powers of all their past enemies. This would be a great story as it showcases the unity and combined strength of the Precure girls.
One idea could be an OC who has the power of music in the Precure world. She could use melodies to heal or empower others. Another idea is an OC from a different dimension who comes to the Precure world with unique powers and has to learn how to fit in and fight alongside the Precure. Maybe an OC that is half - human, half - magical creature and has to hide her true identity while being a Precure.
One idea could be a redemption arc for a previously disliked character. Maybe they team up with an unexpected ally and prove themselves in a series of challenges that are different from the ones in the show, like underwater maze races. Another could be a love triangle between three of the all - star contestants that causes drama both on and off the challenge field.
One idea could be a crossover with another magical girl series like Sailor Moon. The Smile Precure girls could meet the Sailor Scouts and they team up to fight a common enemy that threatens both their worlds. Maybe they have to combine their powers in new and unexpected ways.
A great plot could be that the Precures lose their memories but still feel a strong urge to fight evil. They would have to figure out who they are and what their powers are while still protecting the world. Or, you could write a fanfiction where a new villain emerges who can control the stars in a different way than the previous ones. This would force the Precures to come up with new strategies to defeat the villain.
Perhaps a plot where the eliminated contestants decide to rebel against the rules of the Aftermath. They could form a group and try to change the way the show is run, demanding more fair treatment or better living conditions. This could lead to a lot of drama and conflict, as well as some interesting character interactions.
An interesting plot for a Total Drama All Stars OC fanfic could be an OC who is a master of disguise. They use this skill to trick other contestants in various challenges. For instance, in a mystery - solving challenge, they disguise themselves as different characters to gather information without being detected. Also, the OC could have a secret mission related to a family feud that dates back to a previous season's contestant, adding an extra layer of drama to the story.
One popular idea is an alternate universe where the Precure characters have different powers or backstories. For example, they could be in a steampunk world. Another idea is a crossover with other popular magical girl series. This can bring new and interesting dynamics. Also, a fanfic about the Precure's daily lives outside of their heroic duties, like going to school or dealing with family, can be quite engaging.
One idea could be to explore the origin of the stars. Maybe in the fanfic, the stars are actually the souls of ancient beings. Another could be a love story set among the stars, where two star - like creatures fall in love while traversing the galaxy.
One idea could be a behind - the - scenes look at the friendships and rivalries among the stars in the 'house of stars'. For example, exploring how two actors who seem to be friends on the surface are actually competing for the same big role.