A Gilligan's Island and 'Star Trek' crossover would be cool. The Starfleet crew could beam down to the island by accident. They might try to help the islanders with their advanced technology. Captain Kirk could befriend the Skipper, and Spock could have some really interesting interactions with the Professor as they both are very logical thinkers. Uhura could use her communication skills to try and get a signal out for rescue, which is something the Gilligan's Island crew has been trying to do for ages.
One idea could be a crossover with 'Lost'. The survivors of the 'Lost' plane crash end up on Gilligan's Island. They could interact with the Gilligan's Island cast, share survival skills, and there could be a clash of cultures. For example, Sawyer's con - man ways might be at odds with the simple - mindedness of Gilligan. Another plot could be a crossover with 'Jurassic Park'. Dinosaurs somehow end up on the island. The Gilligan's Island gang has to figure out how to deal with these prehistoric beasts while still trying to get rescued. Maybe the Professor uses his scientific knowledge to try and find a way to co - exist or get rid of the dinosaurs.
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.
Combining Ginger with Sherlock Holmes would be a great match. Ginger is used to using her charm and wits to get what she wants, and Sherlock Holmes' deductive skills are unrivaled. Holmes could help solve some of the mysteries on the island, like why they keep getting so unlucky with rescue attempts, while Ginger could use her charm to help Holmes interact with the other islanders in a more social way.
One interesting story could be about how they built their shelters. They had to use the natural resources on the island like palm fronds and bamboo to create makeshift huts to protect themselves from the elements.
One idea could be a crossover with another popular animated show like 'Adventure Time'. Finn and Jake could end up on Total Drama Island and compete in the challenges. It would be hilarious to see their different personalities interact with the Total Drama characters.
In a 'naruto on island fanfiction', Naruto might find himself on an island that is constantly changing its geography due to some sort of powerful and unstable ninjutsu. This would force him to constantly adapt and use his ninja skills in new ways. He could also meet a spirit or entity on the island that claims to know his destiny and he has to decide whether to trust it or not. There could be a race of people on the island who are immune to normal ninja attacks and Naruto has to learn their ways to be able to defend himself and communicate with them.
One idea could be that the Turtles from 1987 end up in the 2003 universe and have to adapt to the darker and more serious tone. They could team up with the 2003 Turtles to fight a common enemy like the Shredder. The 1987 Turtles' more light - hearted and comical ways might initially clash with the 2003 Turtles' brooding nature, but they eventually learn from each other.
One idea could be a crossover with Undertale. The characters from Glitchtale could interact with the original Undertale characters in a new and unexpected way. For example, Betty from Glitchtale could team up with Chara from Undertale for some sort of dark plan. Another plot could involve a crossover with a different game like Minecraft. The Glitchtale characters could find themselves in a blocky world, having to adapt to new rules and enemies. Maybe Sans from Glitchtale could use his powers in the Minecraft world in a really creative way.
A great plot idea would be Android 21 crossing into a world where technology is feared. She'd have to prove that not all advanced technology is bad. Also, she could cross into a world of pirates, using her skills to navigate the high seas and fight off other pirates.
A plot idea could involve a magical crossover. Maybe a character from a magical fanfiction world accidentally enters the Wayside School. This could lead to chaos as the normal rules of the school are disrupted. The students might have to learn about magic to help the new character return home, and in the process, they gain some magical abilities themselves for a short time. This could also create new friendships and rivalries among the characters.
A Broly crossover with the Naruto universe could be really cool. Picture Broly in the Hidden Leaf Village, his incredible power causing quite a stir. Maybe he could get involved in the fight against the Akatsuki, using his brute strength in a world of ninjas. It would be interesting to see how he adapts to chakra and ninja techniques.