Another good one is 'Lord of the Rings and Star Wars crossover'. Here, the Force meets the power of the One Ring. Characters like Aragorn and Luke Skywalker might find themselves in situations where they have to learn from each other's combat skills and ideologies.
There's also 'The Lord of the Rings meets Harry Potter'. In this fanfiction, the magical worlds collide. Frodo and Harry Potter end up on a quest together, with Frodo's courage and Harry's magic making for an exciting adventure. It's interesting to see how the different magic systems interact.
A crossover with the Star Wars universe would also be cool. The Jedi could be like the wizards in Middle - earth. Maybe Aragorn could learn some lightsaber skills from the Jedi and use them against the orcs. And the Force could have an interesting interaction with the magic in Middle - earth.
There's also 'Buffy and the Fellowship'. In this fanfic, Buffy somehow gets involved with the Fellowship of the Ring. It's really interesting to see how her modern - day sensibilities and combat skills interact with the more medieval and magical world of Middle - earth. For example, her reaction to the elves and their magic is quite different from what the Fellowship members are used to.
Another concept could be that a character from Lord of the Rings, like Legolas, somehow gets transported to the world of Prototype. There, he would have to adapt to the modern - day setting and deal with the infected. He could use his archery skills and elven agility in a completely different environment. His presence might also cause a stir among the military and scientific communities in the Prototype world, as they try to figure out who he is and where he came from.
Another interesting concept is that Vlad is a lost hero from a far - off land who arrives in Middle - earth. He could use his skills in combat and his knowledge of dark magic to help the Fellowship. For example, he might be able to use his vampiric speed to quickly scout areas or use his charm abilities to deceive the enemy. He could also have a complex relationship with Aragorn, either as a rival or an unexpected ally.
A really cool 'Lord of the Rings' crossover fanfiction is when it crosses with the DC Universe. Superman or Wonder Woman in Middle - earth would be quite a sight. They could use their powers to fight the forces of Sauron. This kind of crossover often explores how the extraordinary powers from the DC side would impact the more medieval - style world of 'Lord of the Rings'.
Well, in 'lord of the rings crossover fanfic', the idea of mixing different species from other fictional works can be really engaging. For example, a crossover with the world of 'Game of Thrones'. The political intrigue of the Seven Kingdoms combined with the epic quest of the One Ring. Characters like Tyrion Lannister could meet Frodo and have some really interesting exchanges about power and survival. Or a crossover with the 'Star Wars' universe. The Force could interact with the magic in Middle - earth in a very unique way, and Jedi could potentially have their own take on the One Ring's power.
One idea could be that the Dragonborn from Skyrim somehow ends up in Middle - earth. Maybe they are mistaken for a powerful wizard due to their Thu'um abilities. Another plot could involve the One Ring being found in Skyrim and the different factions vying for its power, just like in Middle - earth. A third interesting plot would be characters from Lord of the Rings traveling to Skyrim and having to deal with the cold, the dragons, and the political unrest there.
One idea could be that the characters from Middle - earth accidentally stumble into Narnia through a magical portal. For example, Aragorn and Legolas could find themselves in the middle of the Narnian forest and team up with the Narnians to fight a common enemy, like an ancient evil that threatens both worlds.
One idea could be that the vampires from Twilight are drawn to the power of the One Ring. They might see it as a source of great power that could enhance their abilities. Another plot could involve a character from Twilight getting transported to Middle - earth and having to adapt to the new world while also dealing with the threat of Sauron. Or perhaps the werewolves from Twilight could form an alliance with the Ents in Middle - earth, as they both have a connection to nature.
One idea could be that Bilbo Baggins discovers a hidden relic during his adventures in 'The Hobbit' that later becomes crucial in the fight against Sauron in 'The Lord of the Rings'.