Well, for Tony Stark, he might become a bit more laid - back around the Guardians. The Guardians' carefree attitude could rub off on him. He may start to make more jokes and not be as uptight about his technology and plans.
Peter Quill might become more responsible in the presence of the Avengers. He sees how they have a more organized approach to saving the world, and it makes him want to step up his game. He might start to think more about the long - term consequences of his actions instead of just living in the moment.
One exciting plot could be that the Guardians and the Avengers have to team up to stop a powerful cosmic villain who is collecting powerful artifacts from both Earth and other planets in the galaxy. The Guardians' knowledge of the galaxy and the Avengers' understanding of Earth could be combined to track down the villain.
One idea could be that the Infinity Stones are scattered across different planets again. The Avengers and the Guardians have to team up to find them before a new villain does. Maybe Thanos has a long - lost relative who is out for revenge and wants to use the Stones' power for destruction.
One exciting plot twist could be that the Infinity Stones have a different origin in this fanfic. Maybe they were created by an ancient race that both the Avengers and Guardians have to discover together. This would force them to work closely and share their knowledge.
Definitely Thor and Star - Lord. Thor is this god - like being from Asgard, and Star - Lord is a half - human, half - alien space adventurer. Their personalities are quite different. Thor is more noble and straightforward, while Star - Lord is a bit of a scoundrel. But they both have a sense of humor and a love for adventure. They could have some great banter while fighting side by side.
I think the meeting between Thor and Groot would be fascinating. Thor, being an Asgardian god, and Groot, a sentient tree - like creature. Thor might be initially confused by Groot's limited vocabulary ('I am Groot'), but as he gets to know him, he would see Groot's strength and loyalty. Groot could also be intrigued by Thor's lightning powers. And their combined strength in a fight against a common enemy would be a sight to behold.
Well, there could be a huge battle against a common enemy. Maybe Thanos is back again and the combined forces of the Avengers and the Guardians have to use their unique skills to defeat him. For example, Iron Man could team up with Star - Lord to come up with a high - tech plan, while Thor and Drax could be on the front line, using their brute strength.
Well, there could be an epic battle against a common enemy. Maybe Thanos somehow returns and the combined forces of the Avengers and Guardians have to use their unique skills to stop him. The Avengers' strength and strategic planning along with the Guardians' out - of - the - box thinking would make for an exciting story.
Black Widow is another popular character. Her skills as a spy and fighter make her a great addition to any crossover fanfiction. She could be involved in a mission with the Guardians where she has to use her stealth and intelligence to outwit their enemies. Also, her complex backstory gives writers a lot to work with when creating new storylines.
Star - Lord is also very popular. His roguish charm and his connection to the cosmic side of the Marvel universe bring a unique flavor to the fanfiction. Writers love to explore his backstory more deeply and his potential relationships with other characters.
Captain America's noble and leadership - driven personality would likely mesh well with Princess Celestia's regal and wise nature. They could both inspire their respective teams, the Avengers and the ponies. Meanwhile, Thor's god - like and somewhat brash personality might be an interesting contrast to Pinkie Pie's hyper - energetic and random nature. It could lead to some really funny and also touching moments in the fanfic as they get to know each other.