I think Rainbow Dash from MLP would be really interesting. She's bold and loves adventure, so she would probably be very eager to get involved with the Battle Force 5's missions. She could bring her flying skills and speed to the team, and her competitive nature might add some interesting dynamics. Maybe she'd have a friendly rivalry with one of the Battle Force 5 members over who can complete a task faster.
In my opinion, Vert from Battle Force 5 could be a great character to focus on. He's the leader of the team, and if he ended up in the MLP world, he would have to adjust to a completely different environment. His leadership skills would be put to the test as he tries to work with the ponies. He could learn about friendship and magic from the ponies, and in turn, teach them about teamwork and technology. His character arc could involve him becoming more open - minded and adaptable, which would be really fascinating to write about.
Twilight Sparkle from MLP could be an excellent choice. She's highly intelligent and a powerful magic user. In a fanfic with Battle Force 5, she could be the one who tries to understand the technology of the Battle Force 5 vehicles and weapons. Her scientific mind could make her very interested in how their technology works. At the same time, she could use her magic to help the Battle Force 5 in ways they never expected. For example, she might be able to use magic to enhance their vehicle's performance or heal any injuries they get during battles. Her journey of learning about a new kind of power (technology) while also sharing her own (magic) would be full of potential for an interesting story.
Spectra is often a popular choice. His complex character, being an antagonist with his own motives and backstory, offers a lot of room for exploration in fanfiction. Writers can delve into his past, what made him turn against the Battle Force 5, and maybe even explore a redemption arc for him.
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.
Ruby from RWBY could be a great focus. Imagine if she were to encounter the psychic abilities from Mob Psycho 100. She could learn about a different kind of power and how to incorporate it into her fighting style. Her positive and determined attitude would also make for some interesting interactions with the more reserved or complex characters from Mob Psycho 100.
Sinister characters like Adam Taurus from RWBY could also be interesting in a Bloodborne crossover. His already dark and violent nature could be enhanced in the Bloodborne setting. He could form alliances with some of the more sinister forces in Bloodborne, or perhaps he becomes a sort of anti - hero, fighting against the greater evils in the Bloodborne world while still being a morally ambiguous figure.
Definitely Naruto and Twilight Sparkle. Twilight is all about knowledge and magic, and Naruto has his own unique ninja powers. They could have really deep conversations about how their powers work and share knowledge. Maybe Twilight could try to study Naruto's chakra system using her magic, and Naruto could be amazed at how Twilight's magic can do things like levitate objects and create spells.