One interesting storyline could be the Federation from Star Trek discovers the world of Middle - earth from Lotr. Maybe they try to introduce their advanced technology to the Middle - earthlings. For example, they could offer medical help to the injured during battles. Another could be characters from both universes teaming up to fight a common enemy, like a powerful dark entity that threatens both the Federation's space and Middle - earth.
The telepathic abilities of some Star Trek species, like the Betazoids, could blend interestingly with the mind - related magic in Lotr. For example, a Betazoid could potentially communicate with wizards or other magically - attuned characters in Middle - earth on a different level. Also, the transporter technology in Star Trek could have a strange interaction with the magical portals or teleportation - like spells in Lotr.
A lesser - known but very interesting 'Star Trek 2009 Crossover Fanfiction' is 'Star Trek 2009 Meets Firefly'. This one is special because it combines the high - tech future of Star Trek with the scrappy, Western - influenced world of Firefly. The contrast between the two settings makes for a very unique reading experience, and the author does a great job of creating a story that respects both source materials.
In a crossover, the Borg from Star Trek could encounter Skynet. The Borg might see Skynet as a potential source of technology to assimilate. However, Skynet would likely resist assimilation and fight back. This could create a three - way conflict if the humans in the Star Trek universe also see Skynet as a threat and try to take advantage of the Borg - Skynet battle to destroy both.
The cultures in both universes are also ripe for exploration in the crossover. The Federation's values of equality and cooperation in Star Trek contrast with the more hierarchical and often morally ambiguous cultures in Star Wars. A story could focus on how characters from each side learn from or clash with the other's cultural norms.
I really like 'TNG and Stargate SG - 1: The Unexpected Encounter'. In this fanfiction, the crew of the Enterprise - D from Star Trek TNG stumbles upon the Stargate. It's a fascinating read as it explores how the two different technologies and cultures would interact. There are some really cool moments where Picard has to negotiate with the Goa'uld, and Data tries to understand the Ancient technology.
One great 'Star Trek DS9 Crossover Fanfiction' is 'DS9 and the Enterprise Crew'. It combines the unique characters from DS9 with the more well - known Enterprise crew in an exciting adventure. The author does a great job of keeping the personalities of all the characters intact while creating a new and engaging story.
One idea could be that the One Ring somehow ends up in the world of Pirates of the Caribbean. Jack Sparrow, being the wily character he is, gets wind of its power and decides to either use it for his own gain or sell it to the highest bidder. The Fellowship, in turn, has to track it down in this strange new world full of pirates, sea monsters, and cursed treasures.
It can seem strange at first. However, if we think of it in terms of the franchise's influence on the fanfiction and vice versa, it's not so odd. The official Star Trek has inspired a vast amount of fanfiction. And in a way, the existence of that fanfiction is like a feedback loop that the franchise can 'observe'. So, while it's an odd concept literally, it makes more sense when considering the relationship between the two.
One idea could be that the crew of the Enterprise discovers a distress signal from a Star Blazers ship. They then team up to fight a common enemy, like an alien race that is threatening both their galaxies. The different technologies and cultures would create an interesting dynamic.