Another plot could involve a storm that brings a castaway to the island. This person has a different view of the world compared to Nim. They could introduce new technology or ideas to Nim, but also cause some conflict as Nim is used to her own way of life on the island. For example, the castaway might want to build a big shelter using modern techniques which Nim thinks will disrupt the natural beauty of the island.
One idea could be that new, mysterious creatures arrive on Nim's Island. Nim has to figure out where they came from and if they pose a threat. Maybe they are friendly but misunderstood, like the new animals could be some kind of magical beings that only come out at night and Nim has to learn their language to communicate with them.
Nim herself is of course very interesting. You can explore more of her inner thoughts and her relationship with the island in different situations. Her father also makes for an interesting character. You could write about his adventures before coming to the island and how those experiences shape his relationship with Nim. Jack, from the movie, can also be included. He could come back to the island with new stories and challenges for Nim.
One plot idea could be the discovery of a new species on Skull Island that has the ability to communicate telepathically with the main character. This new species could lead the character on a quest to find a hidden relic that has the power to control the island's natural disasters.
One idea could be that the gang discovers the zombies are actually victims of a mad scientist's experiment gone wrong. They have to find a way to reverse the process.
One idea could be to write about a hidden treasure on the island that Gilligan accidentally discovers. Maybe it's a long - lost pirate treasure that the castaways then have to figure out how to share and protect from outside forces.
One idea could be that a mysterious ship arrives on the island, but it turns out to be a time - traveling vessel. The castaways have to decide whether to take the risk and go with it to a different era. Another could be that Gilligan discovers a hidden cave filled with strange artifacts that seem to have magical powers. They could then use these powers to try and finally get off the island.
One common theme is friendship. Writers might explore how Nim and Edmund form a strong bond. Another theme could be adventure, with them going on exciting quests together.
One idea could be a story where the Mandalorian has to team up with an old enemy to fight a new, greater threat. Maybe a powerful Sith Lord emerges and they have to put aside their differences.
One idea could be exploring a different origin for Toothless. Maybe he was part of an ancient dragon tribe that was thought to be extinct. Another could be a story where Hiccup discovers a new dragon species that has unique abilities and forms an alliance with them. A third idea is a time - travel fan fiction where Hiccup goes back in time to prevent a great dragon war from ever starting.
A great plot for Warframe fan fiction could be a Tenno getting trapped in a parallel dimension where the rules of the Origin System are all messed up. They have to find a way back while dealing with strange versions of familiar enemies. Or perhaps a story about a Tenno who discovers a hidden Orokin vault that contains not only powerful weapons but also a secret that could change the balance of power in the Origin System. Also, a plot about a Tenno's struggle to control a newly acquired and extremely powerful Warframe that has a mind of its own could be really engaging.
Well, you could have a survivor fan fiction where a contestant has a hidden skill, like being able to communicate with animals on the island. This could give them an edge in finding food and avoiding danger. Or perhaps a story where there's a traitor within the group, someone who is secretly working with the show's producers to create more drama. Also, a plot where the survivors find a map that leads to a hidden part of the island with a bountiful supply of food and shelter.