You could write a fanfiction where Steve and Bucky have to team up with some new characters to take down a Hydra remnant. This new team could have different abilities and personalities that create interesting dynamics. Also, a story about Bucky trying to adapt to the modern world while still dealing with his past as the Winter Soldier could be really engaging. He could struggle with things like technology and new social norms while also trying to find his place in Steve's life again.
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 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.
The plot mainly revolves around Captain America's discovery of a conspiracy within S.H.I.E.L.D. He teams up with the Winter Soldier, who has a complex past tied to Cap. There are intense action sequences as they fight against Hydra agents who have infiltrated S.H.I.E.L.D.
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 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.
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.
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.
Another idea is that there's a villain who can manipulate time and space. He sends Captain America to the Naruto world during a crucial time in Naruto's story, like right before a big battle. Captain America's leadership and battle experience help Naruto and his friends come up with a better strategy. And in the process, they learn from each other's values and fighting styles.
One plot idea could be an OC who is a scientist during World War II and teams up with Captain America. They could work on some top - secret projects together. Another is an OC who is a foreign agent sent to assess Captain America's abilities and ends up becoming his ally. Maybe an OC from the future who travels back in time to help Captain America prevent a major catastrophe that wasn't in the original timeline.
One idea could be a story where Falcon and Winter Soldier have to team up with an unexpected ally from their past. Maybe an old enemy who has a change of heart and holds the key to stopping a new threat.
Another interesting plot could be centered around a new threat that specifically targets Sam and Bucky because of their connection to Captain America. This threat could be a powerful and mysterious organization that has been observing them from the shadows. The story could focus on how they uncover the motives of this organization and fight back.