One common theme is friendship development. Since they are from different backgrounds in the story's universe, fanfictions often explore how they become friends and understand each other better.
You can try searching on fanfiction websites like Archive of Our Own (AO3). There are often a wide variety of fanfictions about different pairings, including Kuroko x Nash. Just use the search function on the site and type in the pairing name.
One great Akashi x Kuroko fanfiction is 'The Red and the Blue'. It beautifully delves into their relationship, showing how Akashi's dominant personality and Kuroko's calm nature complement each other. The author does an excellent job of portraying their emotions in a Yaoi context.
Friendship is a very common theme. They often start as teammates or rivals on the basketball court and then develop a strong bond. Another common theme is growth. Both characters grow as individuals and in their relationship with each other.
The plot could be that Kuroko is constantly being watched over by the GOM members who are overly protective. They might try to keep him away from dangerous opponents in basketball games because they don't want him to get hurt, but Kuroko feels a bit suffocated by their overprotectiveness and tries to prove that he can handle himself.
A common theme is the struggle for independence within the relationship. Kuroko may struggle to maintain his own identity while Akashi is being possessive.
One common theme could be the exploration of their intense emotional connection. Since Akashi and Kuroko have a unique relationship in the original work, in the fanfiction, it might be intensified in a more romantic or passionate way. Another theme could be the contrast between their personalities. Akashi's strong and dominant nature with Kuroko's more reserved and calm self, which can create interesting dynamics in the story.
One popular story could be 'The Bond Beyond the Court'. It focuses on their unique friendship off the basketball court, exploring how they support each other through personal challenges. Another might be 'Shared Dreams', which delves into their mutual love for basketball and how they inspire one another to reach for greater heights in the sport. And there's also 'Silent Understanding', a story that really emphasizes the unspoken connection between Kise and Kuroko.
Fanfiction.net is also a great place. There are tons of fan - created stories, and many fans of the kise x kuroko pairing post their works there. However, the site's interface might be a bit old - fashioned compared to AO3, but it's still worth checking out. You can also look for dedicated fan communities on platforms like Tumblr, where sometimes users share links to their favorite kise x kuroko fanfictions.