One popular pairing is 'Dark Shadows' with 'Twilight'. The idea of the supernatural elements from both universes colliding is really interesting. For example, the vampires in 'Dark Shadows' interacting with the vampires and werewolves in 'Twilight' can create some really unique storylines.
Some fans also like to cross 'Dark Shadows' with 'Harry Potter'. Imagine the wizards and witches from Hogwarts dealing with the strange happenings in Collinsport. The contrast between the magic in 'Harry Potter' and the more gothic, horror - based magic in 'Dark Shadows' can make for some very engaging fanfiction.
In Dark Kakashi fanfiction, a pairing that has gained popularity is Kakashi with characters from the 'Hellsing' universe. The dark and violent nature of both Kakashi's darker side and the Hellsing world can create some intense and action - packed stories. Additionally, Kakashi crossovers with characters from the 'Tokyo Ghoul' series are also quite common. His own inner demons can be paralleled with the struggle of the ghouls in that world.
A very popular pairing is Elden Ring and Bloodborne. The Lovecraftian horror elements of Bloodborne blend well with the dark and mysterious world of Elden Ring. Fans often write about the hunters from Bloodborne exploring the Lands Between, and the unique interactions that would occur.
The pairing of the Lord of Cinder and an unnamed maiden is also seen in some Dark Souls 3 fanfictions. The idea of a powerful, often misunderstood Lord of Cinder finding love with a seemingly ordinary maiden is a popular trope. It plays on the contrast between power and vulnerability, and how their relationship can change the course of the story in the fanfiction.
Another good place is FanFiction.net. Many fans post their 'Dark Shadows' crossover works there. However, the quality can vary. Look for stories with high ratings and lots of reviews. Sometimes, checking out the works of authors who are known for writing good 'Dark Shadows' content can also lead you to great crossovers.
Often, Shu and Inori are paired in crossovers as they are the main characters in Guilty Crown. Their relationship is central to the story, so it's natural to see them together in crossovers. Another popular pairing could be Shu with a character from the crossover anime who has a similar power or personality trait.
Naruto and Hermione from Harry Potter is a fairly popular pairing. It combines the magic of the wizarding world with Naruto's ninja skills. Another one is Naruto and Luffy from One Piece. Their energetic and adventurous personalities make for an interesting combination.
Some fanfictions might pair Castiel and Cisco Ramon. Castiel's otherworldly nature and Cisco's scientific mind could lead to some really interesting interactions. For example, Cisco could be fascinated by Castiel's angelic powers and try to find a scientific explanation for them, while Castiel could be intrigued by Cisco's tech - savvy ways.
One popular pairing is Joker with characters from the Persona series like Akechi. Their complex relationship in the game makes for interesting crossovers. Another is Joker with characters from other RPGs, such as Link from The Legend of Zelda. It's cool to see how their different abilities and personalities interact. Also, Joker and characters from the Final Fantasy series like Cloud are quite popular.
One popular pairing could be Naruto and Akane. Since Naruto has a big heart and is always eager to befriend others, he might be able to break through Akane's tough exterior and they could form an interesting relationship.
A very popular pairing is Elsa and Anna from Frozen with other princesses. For instance, Elsa and Anna meeting Rapunzel. Their stories of sisterly love can contrast and complement the relationships of other princesses. Another popular one is Ariel and Belle. Ariel's curiosity about the human world that Belle is so much a part of, and Belle's admiration for Ariel's adventurous spirit make for an interesting crossover. Also, Moana and Mulan are often paired. Moana's connection to the ocean and Mulan's military skills can create some exciting storylines when they cross paths.