Definitely Steven and Dipper. Steven is so open - hearted and has a positive outlook, while Dipper is more skeptical and curious in a different way. Their different personalities could lead to some really interesting exchanges as they try to understand each other's worlds.
I think Mabel and the Crystal Gems would be great. Mabel's fun - loving and zany personality would contrast with the more serious and mission - focused Gems. She could bring out a different side of them, like getting Amethyst to be even more goofy or making Pearl loosen up a bit.
Definitely Dipper and Pearl. Dipper is always eager to learn about the unknown and Pearl is full of knowledge about Gem history and technology. Their conversations could be really interesting as they share their insights on different mysteries.
Definitely Star and Dipper. Star is this wild and powerful magical girl, and Dipper is the curious and knowledge - seeking boy. They could share their knowledge about the different kinds of magic and mysteries in their respective worlds. For example, Star could show Dipper some of her spells, and Dipper could introduce Star to his research on the strange happenings in Gravity Falls.
The interactions between Ford Pines and Danny's parents could be fascinating. Ford, with his vast knowledge of the strange and supernatural, might be intrigued by Danny's parents' attempts at ghost hunting, even if their methods are a bit more primitive compared to his own scientific investigations. Meanwhile, Danny's parents might be in awe of Ford's knowledge and the things he has discovered in Gravity Falls. This could lead to some comical moments as well as some interesting exchanges of ideas about the nature of the supernatural.
Rick and Dipper would be really interesting. Rick's cynical and scientific view would clash with Dipper's curious and somewhat naive nature. Dipper would be both fascinated and a bit intimidated by Rick's intelligence and his access to other dimensions. Rick might see Dipper as a young, impressionable mind that he could either corrupt or mentor in a strange way.
Sakura and Pearl could also have an interesting dynamic. Sakura is a strong - willed kunoichi who has worked hard to become a great healer and fighter. Pearl is elegant and highly skilled in combat. They could exchange their knowledge of combat techniques and healing methods. Pearl could teach Sakura some of the more refined Gem - style fighting moves, and Sakura could show Pearl how to use her medical skills in more practical and efficient ways during a fight.
Rick and Grunkle Stan would be really interesting. They're both kind of cynical in their own ways. Rick could be dismissive of Stan's 'hustles' at first, but then they might find common ground in their experiences dealing with the strange and unknown. They could end up swapping stories about the weird things they've seen in their respective universes.
One possible plot could be that Steven and the Crystal Gems end up in Gravity Falls. They could team up with Dipper and Mabel to solve a mystery that involves both the magic of Gravity Falls and the Gem technology. Maybe there's a Gem hidden in Gravity Falls that has been causing strange phenomena, and together they have to find and deal with it.
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.
Grunkle Stan and Toriel could be an interesting pairing. Grunkle Stan is a bit of a con artist but has a good heart deep down. Toriel is a motherly figure. They could have some great interactions where Toriel tries to get Stan to be more honest and kind, while Stan might try to find some business opportunities in the Undertale world. It would be a clash of personalities but also a chance for growth for both characters.