Another possibility is Thor and Poseidon. Since they are both gods in their respective mythologies, they might have an understanding of each other's power levels and domains. Thor's control over lightning and Poseidon's over the sea could be combined in some creative ways during battles. They might also bond over their love for their families and their roles as protectors in their own worlds.
It could also be Annabeth and Black Widow. Both are highly intelligent and strategic. Annabeth's knowledge of architecture and ancient languages might be useful to Black Widow in certain situations, like deciphering an ancient code related to a new threat. Black Widow, in turn, could teach Annabeth some self - defense and espionage skills. They would see the value in each other's abilities and form an alliance quickly.
I think it would be Magnus Chase. Since Magnus has experience with the Norse world and Percy is used to dealing with the demigod stuff, they could combine their knowledge and skills. Also, they both have a sense of justice and would likely work well together.
Another possibility is that Tony Stark and Nami would be the first to start an alliance. Nami is always interested in valuable things, and Tony has a lot of high - tech gadgets. They could start a business - like relationship at first, with Nami being intrigued by Stark's technology and Stark being impressed by Nami's navigation skills and her ability to handle money. This could then lead to a full - fledged alliance between the two groups.
I think Captain America from the Avengers would be one of the first to consider an alliance. He's all about justice and protecting the world, and when he sees the SG1 team's efforts in exploring and protecting the galaxy, he would recognize their similar goals. Also, Daniel Jackson from SG1 is very open - minded and interested in different cultures and people, so he would be quick to see the potential in teaming up with the Avengers.
Probably Naruto and Iron Man. Iron Man is always interested in new technology and abilities. When he sees Naruto's unique ninja abilities, especially the jutsu like Rasengan which is like a concentrated energy attack, he would be intrigued. Naruto, on the other hand, would be interested in Iron Man's high - tech gadgets. So they would start an alliance based on mutual curiosity and the potential of combining their skills.
Percy and Carter would be likely to form an alliance. Percy is used to leading and being in dangerous situations, and Carter has a similar sense of responsibility. They both have powers related to water in a way (Percy's direct control of water and Carter's connection to the Nile). Their leadership skills would make them work well together to face any common threats in the crossover world.
Iron Man would be a likely candidate. Tony Stark is known for his sense of humor and ability to tolerate eccentric personalities. He might see Deadpool's skills and be interested in using him for certain missions, while also enjoying the banter.
I think Hamilton and Captain America would be likely to form an alliance. They both have strong beliefs in justice and freedom. Captain America fought for his country in a different time, and Hamilton was a key figure in the American Revolution. They could understand each other's values and work together towards some common goals, whether it's about protecting the people or promoting certain ideals.
I think Yugi and Captain America would be likely to form an alliance first. Yugi is a kind - hearted and brave character, and Captain America is all about justice and leadership. They would recognize these qualities in each other quickly and start to work together to face the challenges in the crossover situation.
I think Harry Potter and Captain America would be likely to form an alliance. Harry is a natural leader who has faced great evil in his world, and Captain America is all about justice and doing what's right. They would respect each other's values and leadership skills. They could lead their respective teams, the Hogwarts students and the Avengers, in the fight against the common enemies like Voldemort and Thanos.
Spiderman himself could be the one to initiate an alliance. He's used to working with other heroes and he has a friendly personality. When he meets the Batfam, he would see the potential in working together and might reach out first. He would probably start with some light - hearted banter to break the ice and then suggest they team up to take on the bad guys in Gotham.