A crossover with One Piece might also work well. Joseph Joestar could find himself on the Grand Line, interacting with the Straw Hat Pirates. His hamon abilities could be a strange and new power for the pirates to encounter, and he could help them out in battles against the likes of the World Government or other powerful foes, while also learning about the Devil Fruits and Haki.
One idea could be the Persona characters getting sucked into the JJBA universe. For example, the Phantom Thieves could end up in Morioh and have to deal with Stand users while trying to find a way back home. They might team up with Josuke and his friends to fight a common enemy that's causing chaos in both their worlds in a strange way.
One idea could be a crossover with another popular anime like Naruto. For example, Jotaro could meet Naruto and they could have a battle of wills and powers. Naruto's positive attitude might clash with Jotaro's more stoic nature.
Well, you could focus on the character crossovers. Imagine Jotaro Kujo meeting Ichigo Kurosaki. Jotaro's cool and collected demeanor would contrast with Ichigo's more hot - headed nature. They could learn from each other's fighting styles. And then there's the possibility of Stand users having to adapt to the spiritual energy in the Bleach world and vice versa. This could lead to some really interesting power - up and training sequences for the characters involved.
Kakyoin and Luffy from One Piece would be an unexpected but fun pairing. Kakyoin's calm and strategic mind would be an interesting contrast to Luffy's carefree and impulsive nature. They could work together in a battle, with Kakyoin using his Hierophant Green to create distractions or attack from a distance while Luffy charges in head - first, using his Gum - Gum powers to take on enemies directly.
Akira and Giorno would make an interesting pairing. Akira has his leadership skills and the ability to use Personas, while Giorno has his determination and powerful Stand, Gold Experience. They could learn from each other's sense of justice and different ways of achieving their goals. Akira could teach Giorno about the power of the collective, as the Phantom Thieves work as a team, and Giorno could show Akira how to be more assertive and decisive in his actions.
One interesting idea could be a crossover with "Moana". Elsa's ice powers and Moana's connection to the ocean could create a really cool dynamic. Maybe Elsa accidentally freezes part of Moana's ocean and they have to work together to fix it. Another could be with "Tangled". Rapunzel's long hair and her adventurous spirit combined with Elsa and Anna's journey in Frozen 2 would be exciting. Rapunzel could use her hair to help them climb mountains or cross chasms. A third idea is a crossover with "Beauty and the Beast". Belle's love for books and knowledge could help Elsa understand more about her powers and the history of magic in the Frozen world.
A Thundercats and Star Wars crossover fanfiction would be really cool. The Thundercats could be in the Star Wars universe, and their unique powers and weapons could be a great addition. Maybe the Thundercats could help the Jedi or the Rebels in their fight against the Sith or the Empire. For instance, Cheetara's speed could be useful in battles, and Tygra's illusions could be used to deceive the enemy.
Well, first, the fanfic should respect the lore of both SCP and JJBA. If it starts messing up the basic rules of either franchise, it can be a turn - off. The pacing is also crucial. A good crossover will have a well - paced story that doesn't rush through the interactions and developments. And finally, the world - building. How the two universes are merged should be creative and believable, like how the locations from JJBA fit into the SCP facilities or vice versa.
A Digimon and Sailor Moon crossover is an interesting concept. The Digimon could help the Sailor Scouts in their battles against the Dark Kingdom. The magical powers of the Sailor Scouts combined with the digital powers of the Digimon would create a really unique and exciting story. And a Digimon and Avatar: The Last Airbender crossover. The Digimon could be part of the different nations, and they could use their abilities to help Aang and his friends in their quest to restore balance.
One idea could be an Atreus crossover with the world of Harry Potter. Atreus could be a new student at Hogwarts, bringing his own unique skills and knowledge from his Norse mythology background. He might struggle to adapt to the magic of the wizarding world while also showing off his own combat and survival abilities.