Thor might initially go into denial. He can't believe that Loki is truly gone. He may hold Loki's body for a long time, as if waiting for him to come back to life. Then, he could become angry. Angry at the situation, at whoever or whatever caused Loki's death. Eventually, he may find solace in the memories of Loki. Remembering the good times they had together and using those memories to move forward.
Well, in this 'avengers meet frigga fanfiction', it could center around Frigga using her magic to help the Avengers in some way. She might be a key to solving a mystery that the Avengers are facing. For example, she could have knowledge about an ancient artifact that the bad guys are after, and she teams up with the Avengers to keep it safe. Also, there could be some emotional moments as the Avengers, who have lost so much, find a mother - like figure in Frigga.
It varies a lot depending on the specific fanfiction. Some might depict it as a grand event in a mythical era, while others could have a more modern or alternative take.
The theme of sacrifice is also present. Frigga might sacrifice her own well - being or reputation to protect Loki. In some fanfictions, she takes risks to save Loki from danger, whether it's from external threats or from the consequences of his own actions. This shows the depth of her love for him.
In many fan fiction scenarios, Odin slapping Frigga might be part of a complex plot twist or a reflection of their tumultuous relationship. It could be related to power struggles, hidden secrets, or emotional conflicts.
Maybe the Deathly Hallows have some sort of connection to Asgardian artifacts. Harry, in his role as the Master of Death, starts to investigate this connection and ends up in Thor's world. Thor initially doubts Harry but as they face challenges together, like an army of dark creatures from the wizarding world invading Asgard, they become friends and allies.
Well, in such a fanfiction, perhaps Harry Potter, being the Master of Death, has some knowledge or power that Thor needs. For example, if there is a dark force in Asgard that is related to death in some way, Thor might seek Harry's help. Their encounter could lead to a cultural exchange too, with Harry learning about Norse mythology and Thor about the wizarding world.
Harry could use his invisibility cloak to his advantage in Thor's world. He could spy on enemies or gather information without being detected. His ability to communicate with spirits as the Master of Death might also give him an edge. He could perhaps communicate with the souls of fallen Asgardians and learn their secrets.
Archive of Our Own is a great place to start. It has a large collection of fanfics, and you can easily search for 'loki loves frigga'. The tagging system there helps you narrow down the results based on what you're interested in, like the genre or the length of the story.