Another option is Wattpad. While it has a wide range of content, there are definitely some interesting 'Captain America: The Winter Soldier' fanfictions on there. Some writers may post exclusive content on Wattpad, so it's worth checking out.
One great piece of fanfiction could be 'The Long Road to Redemption'. It focuses on the relationship between Captain America and Winter Soldier as they navigate through the aftermath of all the chaos in their lives. It delves deep into their emotional bond and how they support each other to heal.
There's a fanfiction called 'Redemption of the Winter Soldier'. In this story, Bucky tries to make amends for his past actions as the Winter Soldier in a more complex and detailed way than in the movie. It's really engaging as it shows his internal struggle. Also, 'Steve's Choice' is a story that explores the choices Steve has to make regarding Bucky and his role as Captain America, and it's a great read.
Black Widow would be a great character to further involve. She has a complex past and her skills could add more depth to the story. Sam Wilson, too. His friendship with Steve could be explored more, and he could play a key role in helping Bucky adjust to the modern world. Another good addition could be Agent 13. She could be involved in some sort of undercover mission related to the Hydra secrets that are still out there.
There's 'Ava', an OC who is often depicted as a skilled sniper. She teams up with Captain America and helps him take on Hydra agents. Then there's 'Max', an OC with super strength. He was experimented on by a rogue Hydra faction and ends up fighting on the side of good. Another popular one is 'Luna', an OC who has the ability to manipulate minds. She uses her power to help the Winter Soldier break free from some of his mental programming.
One idea could be an OC who is a scientist that gets caught in the middle of the conflict between Captain America and the Winter Soldier. She has to use her knowledge to try and stop the chaos while also dealing with her own secrets. Another could be an OC who is a long - lost friend of Bucky from before he became the Winter Soldier. This OC tries to bring back Bucky's memories. A third idea is an OC who is a new recruit in SHIELD and idolizes Captain America. He gets involved in the events and has to grow up fast to face the challenges.
A plot could involve an alternate universe where Bucky was never captured by Hydra. He and Steve continue their adventures together, fighting different villains. Or perhaps a story where the Winter Soldier is sent on a mission to assassinate Steve, but at the last moment, his true self starts to break through and he has to fight against his programming to save Steve.
One way is to read reviews or summaries of the fanfiction before starting. This can help you find the ones that are more likely to be interesting to you. For example, if you prefer action - packed stories, look for reviews that mention lots of fight scenes in the 'Captain America: The Winter Soldier' fanfiction.
Another theme is loyalty. They are extremely loyal to each other. In fanfics like 'Loyalty in the Face of Adversity', it shows how they will not abandon each other no matter what the situation is, whether it's fighting against a common enemy or dealing with internal conflicts.
The story of 'Captain America: Winter Soldier' is complex. It mainly revolves around Steve Rogers adjusting to the modern world. Hydra has secretly infiltrated S.H.I.E.L.D. The Winter Soldier, Bucky Barnes, who was Steve's old friend, has been brainwashed by Hydra to be a deadly assassin. Steve discovers the truth about S.H.I.E.L.D. and Hydra's plot. He teams up with Natasha Romanoff to fight against this conspiracy and also tries to save his friend Bucky from the control of Hydra.
The Winter Soldier doesn't become Captain America in the regular comic storylines. It's Steve Rogers who holds that position. But comics are full of surprises and alternate universes, so there could be special instances where this happens in some less common or alternate versions.