I think Harry and Steven would be the most interesting. Harry has his own burdens of being the 'Chosen One' in the wizarding world, and Steven has to deal with his role as a half - Gem. They could understand each other's struggles and learn from each other's ways of handling difficult situations.
Probably Hermione and Pearl. Hermione is extremely intelligent and loves to study, and Pearl is very knowledgeable about Gem history and culture. They could exchange knowledge and maybe even create something new together. Hermione could introduce Pearl to the world of books and academics in the human world, while Pearl could show Hermione the wonders of Gem technology and lore.
I think Mr. Incredible and Hagrid would be a really interesting combination. Mr. Incredible's no - nonsense attitude and his physical strength combined with Hagrid's love for magical creatures and his knowledge of the wizarding world would make for some great interactions. They could both be involved in a mission to protect a rare magical creature from some villains who want to use it for evil purposes.
I think Harry Potter and Snow White would be an interesting combination. Harry is used to fighting dark magic and Snow White has her own charm and innocence. Harry could protect Snow White from the Evil Queen using his magic skills, and Snow White could teach Harry about the power of hope and kindness in a more fairy - tale - like way.
Steven himself would be very interesting. His kind - hearted nature and unique powers would stand out among the Avengers. He could bring a new perspective to the team.
I think it would be Ben. His ability to transform into various aliens brings a lot of possibilities. He can be a tough fighter like Rath or a strategic thinker like Grey Matter. In the crossover, seeing how he interacts with the Gems and Steven would be really fascinating.
A great character combination would be Pearl and Vegeta. Pearl is very elegant and precise in her movements, much like Vegeta. Also, both are very proud characters. They could start off as rivals, constantly trying to outdo each other in combat skills or knowledge. But as the story progresses, they might come to respect each other's strengths and learn from one another. Their combined presence would bring a lot of intensity and drama to the fanfiction.
Shaggy and Amethyst could be a great combination. Shaggy is always a bit of a scaredy - cat but also has a big heart. Amethyst is laid - back and loves to have fun. They could bond over their love for food and their easy - going attitudes, while also helping each other out during the adventures. Shaggy might be hesitant at first when facing gem - related dangers, but Amethyst could encourage him and show him that there's nothing to be too afraid of.
I think Aerith and Hermione would be a really interesting combination. Aerith has her connection to the planet and her gentle nature, while Hermione is highly intelligent and resourceful. They could combine their knowledge, with Aerith teaching Hermione about the life force of the planet and Hermione sharing her vast magical knowledge. It would be a great exchange of ideas and skills.
I think Harry Potter and Tohru Honda would be an interesting combination. Harry has been through so much trauma and has a strong sense of justice. Tohru, on the other hand, is kind - hearted and has a way of bringing out the best in people. Their meeting could lead to Harry learning more about emotional healing from Tohru, and Tohru getting to experience the wonder of magic.
I think Hermione and Superman would be an interesting pair. Hermione is all about knowledge and learning, and Superman, with his alien origin and super - intelligence, could share a lot with her. They could exchange ideas about their respective worlds, and Hermione might even find a way to use magic to enhance Superman's powers or help him in some way.
Enid from OK KO and Pearl from Steven Universe. Enid is a bit of a cool, laid - back character with her own brand of strength, and Pearl is a very refined and skilled gem. They could have a great dynamic, like Enid teaching Pearl some modern - day Earth things, and Pearl showing Enid some of her elegant combat moves.