The key element is the discovery of abuse. Benny has to find out that Billy is being abused in some way, whether it's physical, emotional or both. Another element is Benny's reaction. He has to be determined and brave to take on the role of protector.
Well, one important element is the relationship between Benny and Billy. It has to develop in a way that makes it believable for Benny to want to protect Billy. Also, the portrayal of the abuse has to be done carefully so as not to be too graphic or offensive. And the way Benny overcomes the obstacles in protecting Billy, like dealing with the abuser or getting help from others, is also a key part.
One possible fanfiction could be 'Benny's Shield'. In this story, Benny discovers the abuse Billy is going through and decides to be his protector at all costs. He stands up to Billy's abuser and helps Billy regain his confidence. Another could be 'Billy's Guardian Angel Benny' where Benny uses his wits and courage to keep Billy safe from harm.
One good one could be 'Billy's Redemption'. It shows how Billy, after being abused, slowly starts to heal with the help of some friends in the story. The author does a great job of portraying his internal struggles.
Fanfiction.net is also a good place. There are numerous fanfictions on this site. However, the search might be a bit trickier compared to AO3. But with some patience, you should be able to find some great 'abused billy hargrove fanfiction'.
One common theme is redemption. Since Billy had a troubled past in the show, many fanfictions focus on him trying to make up for his wrongs. Another theme is family. Exploring his relationship with his father or creating new family - like bonds with other characters. And love, whether it's romantic love or the love he might find in a new group of friends.
One great 'Billy Hargrove OC Fanfiction' is 'The New Girl in Hawkins'. It has a really interesting OC who challenges Billy in unique ways. The story does a great job of integrating the OC into the Stranger Things universe and exploring her relationship with Billy.
There are many great Billy Hargrove fanfictions out there that focus on different aspects like his character development or his relationships in a non - sexual way. You can start by looking on platforms like Archive of Our Own. Just use the filters to exclude any mature or sexual content tags and search for Billy Hargrove. You might find some interesting stories about his friendship with other characters or his journey to redemption.
One common theme is redemption. Many fanfics focus on Billy trying to make up for his past mistakes. Another is his complex relationships, whether it's with his family or friends. And his struggle with his own identity is also often explored.
The Stranger Things universe itself is very popular, so adding an OC to it, especially in relation to a character like Billy, gives fans a chance to explore new storylines. It allows for creativity in filling in gaps in the show or taking the story in different directions. For example, an OC could be a new love interest for Billy, which adds a whole new layer of drama and romance to the existing story.
There is a fanfiction called 'My Heart for Billy'. It has a really interesting plot where the reader is new to Hawkins and catches Billy's attention right away. The way the writer portrays the growing feelings between them is very engaging. Additionally, 'With Billy by My Side' is a story that takes you on an emotional journey. It shows how the reader and Billy support each other through different challenges in Hawkins.
One great fanfiction to check out is 'The Unlikely Bond'. It does a wonderful job of building a relationship between Billy and Steve gradually. Another is 'Hidden Feelings' which focuses on the internal struggles of both characters as they start to fall for each other.