A major part of the fanfiction could be her love interest. Maybe she falls in love with one of the Earth - based Avengers. This would create a lot of drama as they come from different worlds and cultures. Their relationship would face many challenges, like how to deal with the long - distance between Asgard and Earth when she has to return home sometimes.
It could involve her journey to Earth to join the Avengers. Maybe she was sent as an emissary from Asgard to help Earth in its time of need. This would be an interesting start as she'd have to adjust to Earth's customs and the different personalities of the Avengers.
One possible story could be about how this Avenger, as the Princess of Asgard, uses her Asgardian powers and knowledge to help the Avengers in a battle against a powerful new enemy. For example, she might be able to call upon the Bifrost to quickly transport the team to different locations during the fight.
A common plotline is the Asgardian princess sister coming to Earth to seek help from the Avengers. Maybe Asgard is under some sort of threat, like a new powerful enemy has emerged, and she believes the Avengers can assist. Another plotline could be her being exiled from Asgard and finding a new home and purpose with the Avengers.
One possible plotline could be Loki trying to redeem himself in the eyes of the Avengers. He has a long history of causing trouble, so it would be a journey of him making amends. Another plotline could be Loki using his knowledge of the Asgardian and other realms to help the Avengers face a threat from those areas. For example, a new powerful enemy from the Nine Realms emerges and Loki's insights are crucial in the fight.
Probably Heimdall. He guards the Bifrost, the Rainbow Bridge that leads to Asgard. He has the ability to see all, so he'd be the first to spot the Avengers coming. And he's not one to let just anyone pass without a bit of interrogation.
One popular type of fanfiction in this category might involve the sister of Thor or Loki, who is a princess of Asgard, interacting with the Avengers. For example, she could be a powerful magic - user and help the Avengers in their battles against new threats. There are many fanfiction platforms like Archive of Our Own where you can search for such stories using relevant tags like 'Asgard princess' and 'Avengers' to find some great reads.
Well, aside from Thor and Odin, he could meet Sif. Sif is a strong Asgardian warrior, and she might be interested in Harry's unique brand of magic. And of course, there's a high chance of meeting Loki. Loki is always up to something, and his devious nature could either make him an adversary or an unexpected ally to Harry.
In some fanfictions, the 7th Avenger could be a time - traveler from the future. This person has come back to prevent a major disaster that the Avengers couldn't handle without their help. They know all about the future events and use this knowledge to guide the team, but also have to be careful not to change the timeline too much.
He'd probably start by observing. Naruto is curious, so he'd watch how the Asgardians live, their customs, and how they interact. Then he'd start to adapt by using his ninja adaptability skills.
It could be about a character named Felicity being inserted into the Avengers universe. Maybe she has some unique powers or relationships with the Avengers in this fan - made story.
Percy could also be a big fan of Hulk. Just like Percy has his own 'inner beast' that he sometimes has to control (his demigod powers), Hulk has his own anger issues. Percy might see a bit of himself in Hulk and also be in awe of Hulk's raw strength. He would probably be interested in seeing if there's a way to help Hulk better control his rage, using his own experiences of self - control.