Perhaps Loki and Harry find themselves in a situation where they have to swap powers for a day. Loki has to deal with Harry's magic wand and spells, while Harry has to handle Loki's shape - shifting and illusions. This could lead to a series of comical and also character - building moments as they learn from each other.
Another plot could be that Loki, being exiled from Asgard, lands in the wizarding world where Harry lives. Harry, initially suspicious of Loki, gradually discovers that Loki has some valuable knowledge about an ancient magic that could help Harry defeat a new dark force that is emerging. So they form an uneasy alliance and throughout their journey, they both grow and change.
Well, a plot could be Loki disguising himself as a Hogwarts student. He gets involved in the house rivalries and eventually meets Harry. They start off as adversaries but then realize they both have a common goal of protecting the wizarding world from a hidden danger. For example, an ancient evil that is about to be awakened. Loki could use his Asgardian knowledge and Harry his wizard skills to defeat it. Also, Loki could be interested in the magic of the wizarding world and want to learn more, leading to some humorous and interesting interactions with the Hogwarts professors.
In 'Loki adopts Harry Potter' fanfiction, it could be that Loki adopts Harry due to some sort of prophecy. Loki realizes that Harry is crucial in a much larger plan involving both the wizarding world and the Nine Realms. So, he takes Harry under his wing. He might train Harry not only in magic but also in strategy and deception. Harry could then use these skills to form alliances within the wizarding world that were previously unthinkable, like getting the Slytherins to side with him against Voldemort by using Loki - inspired tactics.
One idea could be that Fem Loki, being a mischief - maker, gets transported to the Harry Potter world and decides to play pranks on the Hogwarts students. She might turn the Quidditch pitch into a giant ice rink just for fun.
One plot idea could be that in a magical realm where different fictional universes collide, Harry's appearance or some magical mishap makes others think he is Loki. Maybe the characters from the Thor/Loki universe initially treat him as Loki and he has to figure out how to convince them otherwise while also dealing with the chaos that ensues. For example, he could be caught in the middle of a power struggle between Thor and those who believe he is Loki up to no good.
A third plot idea is that fem Harry Potter is actually a long - lost relative of Loki in some convoluted way. This discovery leads to a series of events where they have to work together to uncover the truth about their shared heritage. Along the way, they face opposition from both the wizarding community who fear her newfound connection and some Asgardians who don't trust an outsider.
Well, a plot could involve Loki and Jane being accidentally transported to a parallel universe where their roles are reversed. Jane has to deal with the politics of Asgard while Loki tries to understand Earth's scientific concepts. Or, perhaps they are both caught in a time - loop where they keep repeating a day, and they have to figure out how to break it together, learning more about each other in the process.
Maybe Harry and Amelia are from two different worlds. Harry is from a world of magic and Amelia from a non - magical world. They accidentally cross paths when a magical portal opens up. They then have to learn about each other's worlds and help each other out in various situations, such as Amelia helping Harry understand non - magical technology and Harry showing Amelia the wonders of magic.
Perhaps in the fanfiction, Vernon discovers a hidden magical talent of his own. Harry, upon finding out, has to decide whether to help Vernon develop it or keep it a secret from the wizarding world as Vernon is a Muggle. This could lead to a lot of comical and tense situations.
One idea could be a time - travel plot where Harry goes back in time and McGonagall is much younger. They form an unexpected bond during a dangerous situation at Hogwarts that gradually turns into a deeper, more romantic relationship. But they have to keep it a secret due to the age difference and the rules of the wizarding world.
A possible plot could be that Harry and Nagin are both chosen for a special task in the wizarding world. They initially clash due to their different personalities but gradually learn to work together and form a strong bond along the way.