One great 'lost crossover fanfiction' could be one that crosses 'Lost' with 'Stranger Things'. It might involve the mysterious island having some sort of connection to the Upside Down. Maybe the smoke monster has a similar origin to the Demogorgon. Another interesting one could be a crossover with 'The X - Files'. The agents Scully and Mulder could be brought to the island to investigate its strange phenomena.
One main theme is the clash of different vampire cultures. Twilight has its more civilized, 'vegetarian' vampires, while Lost Boys are wilder. Another theme is the idea of forbidden love, which is common in both universes. It could be between a character from one and a vampire from the other.
One key element is the clash of the two different worlds. Bella comes from a more normal, if not somewhat supernatural - adjacent world in Twilight, while the Lost Boys live in a darker, vampire - like world. So, the cultural and lifestyle differences are important.
One idea could be a crossover with 'Buffy the Vampire Slayer'. The two strong female leads from each show could team up to fight a common supernatural enemy. Maybe they meet in a dimension where both their worlds collide.
The theme of adventure also runs strong. In crossovers like the one with 'Indiana Jones', the sense of adventure from both universes is amped up. Characters are constantly on the move, exploring new places, and facing dangerous challenges as they navigate the combined worlds of Atlantis and the other franchise.
Well, first, the integration of the different universes. For example, how the creatures or technology from Lost Planet blend with the other crossover universe.
In this fanfiction, the Rangers could also learn from Naruto. His strong will and determination are qualities that the Rangers could admire. Maybe the Red Ranger could learn some of Naruto's training techniques to become even stronger. And the story could revolve around their combined efforts to save both the ninja world and the Lost Galaxy from a powerful, new threat.
A possible plot could involve Luna Lovegood. Luna has always been interested in strange and magical creatures. In the crossover, she somehow ends up in the world of Lost Girl. She quickly befriends Trick, the Blood King. Luna's unique perspective on magic and the unseen helps Trick deal with a problem in his court. Meanwhile, the other characters from both universes are drawn into their alliance, and they all have to face a powerful enemy that is trying to disrupt the balance between the wizarding world and the Fae world.
First, you need to be really familiar with both shows or universes you want to cross over. Know the characters, their personalities, and the rules of their worlds. For example, if you're crossing Lost Girl with something like 'Doctor Who', you have to understand time travel in Doctor Who and the fae lore in Lost Girl.
There's also 'Lost Planet and Mass Effect Crossover'. In this fanfiction, the story often plays around with the different species and technologies from both universes. It delves into how the characters from Lost Planet would interact with those from Mass Effect, like the Krogan and the Lost Planet's Akrid. The plot usually involves some sort of joint mission against a common threat that combines the elements of both games.