From the Street Fighter series, Ryu could be a great addition. Imagine the fight scenes between Ryu's martial arts and X's high - tech combat moves. Their different fighting styles would create some exciting battles and exchanges in the fanfic.
In a crossover with the Final Fantasy series, Cloud Strife could be included. His brooding personality and his powerful sword skills would contrast with X's more robotic nature. They could team up to fight a common enemy that threatens both their worlds, and their interactions would be full of interesting character dynamics.
Zero would be an obvious and interesting character to include. His backstory and his relationship with X could add depth to the fanfic. Also, in a crossover, he could have some unique interactions with characters from other franchises.
Well, you could include Zero from the Megaman series. He has his own unique abilities and a cool backstory. In a crossover, he could bring a different fighting style and perspective. Another good one is Proto Man. He could add some mystery and rivalry elements to the story.
In a crossover with 'Naruto', Naruto himself would be an interesting addition. His love for ramen could be a starting point. He could be amazed by Soma's cooking skills and end up challenging him to a friendly shokugeki. Another character could be Kakashi. His laid - back attitude yet sharp taste buds could add an interesting dynamic. He could be a tough judge in a shokugeki battle.
One idea could be a crossover with Sonic. Imagine Megaman and Sonic teaming up to stop a new villain who is causing chaos in both their worlds. They could combine their unique abilities, like Megaman's weapon switching and Sonic's super speed.
A 'megaman x crossover fanfic' could involve a crossover with the Pokemon universe. X could end up in the Pokemon world and have to work with a trainer and their Pokemon to stop an evil organization that is using technology to harm Pokemon. He could use his weaponry to help in battles against the organization's powerful machines.
In a crossover with 'The Matrix', Neo would be an interesting addition. He could use his skills in the virtual world to help Marty and Doc Brown understand and manipulate the digital aspects of time - travel technology that might be affected by the Matrix. His ability to see the code could potentially help them fix glitches in the DeLorean's time circuits.
Axl can be a great addition. He has his own unique abilities and a bit of a wilder personality compared to X and Zero, which can add some interesting dynamics. Also, Sigma is often included as a major antagonist. His complex motives and powerful presence make for great story material. Another good character is Alia. She can provide support to X and Zero from the base, and her intelligence can be used in various ways in the fanfiction, like helping to analyze enemy weaknesses.
If it's a crossover with a shonen anime like Naruto, Naruto himself could be an interesting addition. His boisterous personality would contrast with Loid's cool and calculated nature. And Anya would be fascinated by his ninja skills.
One idea could be to cross Megaman Zero with another popular game series like Sonic. Imagine Zero running at high speeds through the colorful zones in Sonic's world. Another idea is to cross him with a Final Fantasy world. Zero could be a mysterious warrior in that RPG setting, using his skills to fight against the powerful summons and magic - users there. Also, a crossover with the Metroid series would be cool. Zero exploring the desolate planets and facing off against the space - pirates and Metroids could make for an exciting fanfic.
Pearl would be an interesting character to include. Her grace and combat skills, combined with her complex backstory, could add depth to any crossover. In a crossover with a historical - themed show, Pearl's knowledge of different eras could create interesting storylines. Another interesting character is Garnet. Her fusion status and stoic nature can lead to unique interactions, especially in a crossover with a show that also has characters with dual identities or special powers.
Definitely Twilight Sparkle. Her studious nature and powerful magic would create an interesting dynamic with Discord's chaos. She'd be constantly trying to analyze and fix whatever Discord has messed up. Pinkie Pie is also great. Her zany personality could either match Discord's chaos or be a source of irritation for him. Rainbow Dash would be cool too. Her bravado and flying skills could be put to the test when Discord throws up some wild obstacles in her path.