Well, the 'abusive' aspect is a big differentiator. Most other fanfics usually focus on positive relationships or adventures. But in 'abusive steve x tony fanfic', it likely involves some form of mistreatment between Steve and Tony, which is a very different dynamic compared to the more common friendly or romantic portrayals in other fanfics.
Personally, I don't recommend 'abusive' themed fanfics as they can often contain disturbing content. But if you're set on it, check out fanfic communities on Tumblr. Some users might share or discuss 'abusive steve x tony fanfic', but be cautious as the content quality and nature can vary a great deal.
I really like 'A Different Kind of Team - building'. In this fanfic, Steve and Tony are forced to work closely together on a special project. It delves deep into their personalities and how they gradually understand and fall for each other. It's full of interesting dialogues and character development.
Emotional depth is also important. The fanfic should make the readers feel the connection between Steve and Tony. It can show their conflicts, like their different ideologies in the movies, and how they overcome those differences to be together. Good use of dialogue to convey their feelings and thoughts is also a plus.
Friendship and love are also big themes. The relationship between the three can range from deep platonic friendship to romantic love. In some fanfics, they struggle to define their feelings for each other. They support each other through tough times like battles and personal crises, which shows their strong bond.
One great fanfic could be 'The Three Musketeers of the Avengers'. It shows an interesting dynamic between Steve, Tony and Bucky. They start off a bit rocky but then come together to face a common threat. The author does a great job of exploring their individual personalities within the relationship.
Friendship is a very common theme. Despite their differences, they come together and form a strong bond. Another theme is redemption. For example, Bucky might be seeking redemption for his past actions, and Tony and Steve play a role in that process.
The 'Hydra' element makes the relationship between Steve and Tony much more complex. Normally, Steve is seen as a paragon of virtue, but with the Hydra influence, Tony becomes very distrustful. It's like a complete shift in their usual dynamic. Steve may act in ways that are contrary to his true self, which confounds Tony and makes him both angry and sad.
One great tony x bucky x steve fanfic is 'The Trio's Journey'. It focuses on their unique relationship dynamics, exploring how they support each other during battles and in their personal lives. The characterizations are well - done, staying true to their personalities from the original source material.
One aspect of this fanfiction could be the exploration of the complex relationship between Tony and Steve through the lens of anxiety. Maybe it delves into how their individual anxieties affect their interactions, like Tony's fear of not being good enough conflicting with Steve's anxiety about leading the team well.