It really depends on the theme of the fanfic. If it's about redemption and change, then Lord Farquaad would be more interesting as there's more room for development. But if it's about family and self - discovery, Shrek would be a better choice. For example, if the fanfic is about how Shrek's family expands and how he deals with new challenges in his family life, while still having the shadow of Lord Farquaad in the background.
Lord Farquaad could be the more interesting one. He was a very self - centered and power - hungry character in the movie. A fanfic could explore his backstory more, like what made him so obsessed with power and beauty. Maybe there were some events in his childhood that led him to be this way. By focusing on him, you could give him a chance at redemption or make him an even more complex villain.
One idea could be that Lord Farquaad somehow returns from the dead but has lost his memory. Shrek, instead of seeing him as an enemy right away, decides to help him regain his memory. Along the way, they discover things about each other that they never knew before.
Their interaction would likely be full of tension. Lord Farquaad is used to getting his way and the Gingerbread Man is a spunky character. Farquaad would probably be condescending towards the Gingerbread Man, seeing him as a mere treat. The Gingerbread Man, on the other hand, would not take kindly to Farquaad's attitude and would be sassy in his responses.
I think Legolas could be really interesting. In 'The Hobbit', there are no elves from Mirkwood really involved in the story in the way Legolas is in 'The Lord of the Rings'. So, if you cross over the two, you could explore how Legolas might interact with the dwarves in a different context, considering the historical tension between elves and dwarves. He could also use his skills as an archer in new and unexpected ways, perhaps influenced by the events in 'The Hobbit' that he hears about from Gandalf or other characters.
Black Bolt from the Inhumans would be really interesting. His power of destructive voice is so powerful that he has to be extremely cautious. In a fanfic, he could be the key to solving a major problem, but his inability to communicate easily (because of his power) could create a lot of tension and drama. The Avengers would have to learn to work around his unique situation.
Tsukune would be really interesting. Since he's a human in a world of vampires and monsters, he could be the bridge between different worlds in a crossover. His unique situation and his growing powers could lead to all sorts of interactions. For example, if crossed over with a human - based supernatural series, he could share his experiences of living among non - humans and help those humans understand the other side better.
I think Twilight Sparkle would be really interesting. Her vast knowledge of magic could be used in unique ways in the XCOM universe. She could analyze alien technology and find ways to counter it with her spells. Also, her leadership skills from Equestria could be applied to XCOM operations.
Rock Lee from Naruto would be a great choice. His dedication to martial arts and physical combat would fit well in the world of Baki the Grappler. He could have some intense battles and learn new techniques from the Baki characters.
I think it would be really interesting to focus on Hermione. Her thirst for knowledge would make her eager to learn about the world of Eragon, especially the dragon - riding and the different types of magic. She could also bring her logical thinking and problem - solving skills to the table, which would be very useful in both worlds.
I think Ruby would be a great choice. Her innocence and determination in RWBY could be an interesting contrast to the often more battle - hardened and power - hungry characters in Dragon Ball. She could learn a lot from them about power and also teach them about the importance of friendship and teamwork in a different way.
Ruby would be really interesting. Her innocent and positive attitude would contrast greatly with the dark and desolate Fallout world. She'd be like a ray of hope in the wasteland. Her scythe - fighting skills would also be unique and useful against the various threats in Fallout. She might try to befriend some of the mutants or ghouls, seeing them not as just monsters but as living beings who need help.