One idea could be that Bucky, with his combat skills and knowledge of advanced weaponry from his past, teams up with Shuri, the brilliant Wakandan scientist. They could work together to upgrade Wakanda's defenses. Maybe Bucky has some insights from his time in Hydra that could be used in a positive way when combined with Shuri's innovative thinking.
One interesting fanfiction could be about Bucky Barnes and Black Panther teaming up for a mission in Wakanda. Maybe Bucky is seeking refuge there and T'Challa decides to train him in the ways of Wakanda while also enlisting his help against a common enemy.
There could also be a comrades - in - arms type of relationship. If Wakanda were to face an external threat, Bucky and Shuri could be on the front lines together. Bucky with his combat expertise and Shuri with her technological inventions. They would rely on each other, trust each other's skills, and fight side by side to protect Wakanda.
You can start by looking on Archive of Our Own (AO3). It has a vast collection of fanfictions from various fandoms, and there are likely many that feature Bucky Barnes and Black Panther. Just use the search function and type in their names.
The plot could start with some sort of interdimensional rift that brings Gregor Clegane to Wakanda. Black Panther, seeing this strange and brutish intruder, decides to confront him. At first, Gregor might seem to have the upper hand due to his size and brute strength. But as the battle progresses, Black Panther figures out his opponent's fighting style and starts using his technology, like the energy daggers and his suit's abilities, to gain the advantage. Eventually, Black Panther manages to defeat Gregor and figures out a way to send him back to his own world.
The Black Panther comic has its own unique fictional universe and narrative that is not related to the Black Panther Group. The comic's creation was based on comic book concepts and storytelling rather than any direct connection to the group.
Black Panther would likely win. Black Panther has the advanced technology of Wakanda at his disposal, along with his enhanced physical abilities from the heart - shaped herb. He is highly agile, has superhuman strength, and his suit can absorb and redistribute kinetic energy. Gregor Clegane is a formidable brute in the Game of Thrones universe, but his strength is mainly based on his size and combat experience with medieval weapons. Against Black Panther's high - tech arsenal and superhuman skills, he would be at a disadvantage.
One great 'Black Panther' fanfiction is 'The New Wakanda' which explores a Wakanda that has to face a new, unseen threat. It has great character development for T'Challa and his sister Shuri.
The Legend of Black Panther is an audio novel that can be listened to for free. However, the search results did not provide clear information on which platform could be listened to for free. Therefore, I don't know the specific platform for free listening to books.