Characters from 'Harry Potter' like Hermione and Draco could also be interesting. For instance, if they accidentally end up in the same secret room in Hogwarts while exploring and start to see each other in a new light.
Characters from a popular superhero universe, say Iron Man and Black Widow. They might accidentally be on a mission together that was not originally planned for them both. During this mission, they could develop feelings for each other as they face various challenges side by side.
One popular choice could be characters from the 'Twilight' series. Imagine Bella and Jacob accidentally getting into a situation where they have to work together on a project in Forks. Their relationship could take an unexpected turn towards love.
Goku is always a popular choice. His Saiyan powers and his constant pursuit of becoming stronger make for great storylines. Vegeta is another one. His pride and his own journey to rival Goku can add a lot of drama. And then there's Trunks, with his time - traveling adventures and his unique fighting style.
Kyo Kusanagi is a very popular choice. His powerful fire - based attacks and his role as one of the main characters in the series make him a great focus for fanfiction. Iori Yagami is also popular. His dark and brooding nature, along with his rivalry with Kyo, can lead to some intense storylines. Terry Bogard is another. His classic fighting style and his status as a bit of an underdog - turned - hero give him a lot of potential for interesting fan - created stories.
The IMC soldiers can also be great for crossovers. They have their own set of skills and motives. In a crossover with a stealth - based game universe, the IMC soldiers' combat tactics and equipment could add an element of intrigue.
In 'Naruto Fighter Fanfiction', Naruto and Sasuke are the top picks. But don't forget about Rock Lee. His pure taijutsu skills can make for some exciting fight scenes. Gaara, with his control over sand, is also a very interesting character to feature. Hinata, with her gentle yet powerful fighting style, especially her Byakugan abilities, can also be a great addition to the story.
Arya Stark could be a great character to include. Her skills in combat and her ability to adapt could be interesting when combined with the world of dragons. For example, she could learn to ride a dragon and use her assassin skills to protect it.
Naruto himself is a very popular choice. His journey from an outcast to a hero provides a lot of material for fanfiction. Writers can explore his relationships with other characters more deeply, or create new adventures for him.
Mysterious characters are ideal for 'game of shadows' fanfiction. They can be used to build suspense and keep the readers guessing about their true nature and their role in the game.
Link is of course a very popular character to feature. His journey and his silent but strong personality give a lot of room for creativity in fanfiction. Zelda is also a great choice. Her relationship with Link, her own struggles with her powers, and her role in the story of Hyrule make for interesting stories. Another popular character is Revali. His pride and his unique abilities as an archer can add a lot of drama to a fanfiction.
Alya is also a great character to feature. Her intelligence and strategic thinking can be useful in different crossover scenarios. If crossed over with a science - fiction world, she could be involved in advanced technological research or battles against alien invaders.
Wonder Woman is an obvious choice as she is from Themyscira. She can be paired with characters from other universes like Superman for a DC crossover. In a crossover with the 'X - Men' universe, she could interact with Storm, two powerful female characters with different abilities. Another popular character would be Hippolyta. She could be involved in a crossover where she has to negotiate with leaders from other fictional kingdoms or planets.