Well, identity is a common theme. Percy has to re - establish his identity without the memories others have of him. Another is the theme of revenge in some cases. If he was wronged by those who forgot him, he might seek revenge. And the theme of growth is there too. He grows as a person, becoming more self - reliant and wiser as he deals with the situation of being forgotten.
I've found that 'Percy Forgotten Hero: New Beginnings' is quite good. It begins with Percy waking up in a world that has no memory of him. He has to find his way and prove his worth all over again. There is also a fanfiction called 'Forgotten Percy, Unforgotten Tales' which weaves together old memories of Percy with his new situation. And 'The Forgotten Percy's Ascent' is about Percy rising above the situation of being forgotten and becoming a stronger hero than before.
The 'percy forgotten fanfiction' might be centered around a character named Percy who has been overlooked or forgotten. It could be that the author of the fanfiction wanted to explore the emotions and experiences of a character in such a situation. For example, if Percy was a hero in the original story, being forgotten could lead to a journey of self - discovery as he tries to regain his former status or simply find a new place in a world that has seemingly moved on without him. This could involve him facing challenges, making new allies, or even confronting old enemies who may or may not recognize him.
Percy would feel extremely lonely. He's used to having a support system, and suddenly having that taken away would be devastating. He'd probably feel a sense of confusion as well, constantly wondering why this happened to him.
Well, it could go either way. If the writer wants to create an interesting twist, Percy might be a villain in the Avengers fanfiction. But more often than not, given Percy's own heroic traits from his original story, he'd probably be a hero in the Avengers' universe, helping the Avengers fight against their common enemies.
One possible plot could be that Percy finds himself in a world where everyone he knew has had their memories wiped about him. He might start by trying to figure out what caused this. He could go to his old friends' places, only to be met with blank stares. Then he might try to find a way to reverse the situation, perhaps by going on a quest to find a magical artifact or meet a powerful being. Along the way, he could face challenges alone, as he has no one to rely on, which would force him to grow and discover new abilities within himself.
The main character is Percy. However, in the fanfiction, there could be a new character created specifically for the story, like a young apprentice of Percy who has a unique ability. There may be an old and wise god who has some secrets about Percy's past and is reluctant to share them at first. Also, there could be a group of demigods who are initially skeptical of Percy but then come to believe in him and join his cause as he tries to reclaim his position among the gods.
You could start by looking on popular fanfiction websites such as Archive of Our Own (AO3) or FanFiction.net. Just search for 'percy forgotten' on their search bars and see what comes up.
It could be a demigod who was overshadowed by the more well - known ones like Percy. Maybe someone who was born to a minor god or goddess and got lost in the shuffle. For example, a demigod of a nature god who was always in the background while the big battles were fought by the children of the more prominent Olympians.
I don't think it's overly popular. Fanfiction often focuses on more common themes like Percy's adventures, his relationships with other characters like Annabeth. The 'forgotten god' concept is quite different and might not appeal to the majority of Percy Jackson fans who are more interested in the established storylines and character dynamics.