Loki and Draco Malfoy would be a likely crossover. Loki is the mischievous god in the MCU, and Draco is a bit of a troublemaker in the Harry Potter world. They could team up and cause all sorts of chaos. Maybe Loki would teach Draco some of his more devious tricks, and Draco could introduce Loki to the pure - blood ideology of the wizarding world, which could lead to some really interesting storylines.
Hermione and Sandy could be great for a crossover. Hermione's intelligence and love for knowledge could be paired with Sandy's scientific know - how. They could collaborate on some sort of underwater - land hybrid project, perhaps creating a new kind of magical - scientific device that works both in Hogwarts and in Bikini Bottom.
In 'harry potter flash crossover fanfiction', Harry Potter and the Flash are the obvious front - runners. But aside from them, characters like Sirius Black could be interesting. He has his own set of skills and a rather rebellious nature. Meeting the Flash could result in some exciting adventures. Ginny Weasley, with her courage and talent in Quidditch, might also be a character that fans like to cross over. She could potentially learn some new skills from the Flash or vice versa. And then there's Professor Snape. His complex personality and his skills in potions and the dark arts could create some intense and thought - provoking crossovers with the Flash.
Edward from Twilight could be a likely candidate. His brooding nature and special abilities might make for an interesting interaction with the Jedi or Sith in Star Wars. He could either be seen as a potential threat or an ally. Another would be Ahsoka Tano from Star Wars. Her strong will and combat skills could be interesting when pitted against the vampires of Twilight.
Harry Potter and Nate Ford could be a likely pair. Harry's experience with facing great evils and his leadership skills combined with Nate's strategic mind in planning heists would make for an interesting dynamic. They could learn from each other's methods of problem - solving.
Caleb Prior from Divergent and Ron Weasley might be a crossover. Caleb is intelligent but has his own moral dilemmas, and Ron is a loyal friend with his own insecurities. Their friendship or conflict could be explored in the fanfiction, perhaps with Caleb getting involved in Ron's wizarding adventures and Ron learning about the Divergent world through Caleb.
Well, for sure Harry Potter is a top pick. His connection to Gringotts started early on when he first visited to get his inheritance. Hermione would be there as she's the brains of the group and would be curious about any magical lore associated with Gringotts. Ron, with his family's financial struggles, could also play an important role. The goblin bankers are a given as they are the heart of Gringotts. In terms of crossover characters, if it was a crossover with 'Alice in Wonderland', the Cheshire Cat could make an appearance. It could be lured by the shiny objects in Gringotts and cause some chaos as it tries to steal something, with Harry and his friends having to stop it.
Definitely Harry Potter himself. He's the central character in his own series, so it's likely he'd be involved in any crossover. Hermione Granger could also be a key character as she's smart and curious, and would be interested in learning about the 'Twilight' world. From 'Twilight', Edward Cullen is an obvious choice. His brooding nature and unique abilities would make for interesting interactions with the 'Harry Potter' characters. Also, Jacob Black could be involved, especially when it comes to the 'imprint' aspect as he has his own story arc related to that in 'Twilight'.
Obviously, Harry Potter and Riddick would interact. Harry, being the main hero in his world, would be curious about Riddick's strange abilities and his rough - and - tumble way of life. Riddick, on the other hand, would likely be suspicious of Harry at first but then come to respect his magical powers.
Harry Potter and Ichigo Kurosaki are very likely to be paired. They are both the main protagonists in their respective series. Harry has his strong sense of justice and magical powers, and Ichigo has his determination and Soul Reaper abilities. They could form a great partnership to fight against common enemies.