Yes, one positive aspect could be that it raises awareness about abuse. By portraying Kuroko's situation, it can make readers more sensitive to the issue in real life.
One common theme could be the struggle of Kuroko against the abuse. It might show how he copes with the difficult situation, perhaps by finding inner strength or relying on his friends.
There's a fanfiction called 'Kuroko in the Shadows of Abuse'. In this story, the author uses the abuse as a way to show Kuroko's resilience. It starts with a difficult situation where Kuroko is constantly bullied and abused. But as the story progresses, Kuroko starts to find ways to stand up for himself and fight back. It's a story that shows the strength of the character in the face of such hardships. However, it's not for everyone as the topic is quite intense.
I'm not aware of any 'kuroko tetsuya abused fanfiction' specifically. However, if such fanfiction exists, it's a rather concerning concept. Fanfiction should generally be about exploring positive aspects of characters or creating new and interesting scenarios within the boundaries of respect for the original work and its characters.
Maybe some people want to create shock value. They believe that by writing about an abused Kuroko Tetsuya, they can attract more readers. However, this is unethical as it distorts the character's image. Also, it could be due to a lack of understanding of the positive themes in the original work, which leads them to create such inappropriate content.
To make it more positive, the fanfiction could introduce a mentor figure for Kuroko. This person could help him heal from the abuse and teach him how to be stronger both mentally and physically. Also, the story could end with Kuroko using his experiences to help others who are going through similar situations, turning a negative situation into a positive influence.
In such a fanfiction, perhaps it could start with Kuroko being targeted by a rival team who want to disrupt Seirin's plays. They might kidnap him on his way home from practice. His teammates would then start a frantic search, led by Kagami. They would scour the city, following any leads they could find. In the end, they manage to rescue Kuroko and their bond becomes even stronger through this ordeal.
A possible plot for a Female Kuroko x Akashi fanfiction could be set in an alternate universe where there are no gender - based restrictions in basketball teams. Female Kuroko joins Rakuzan instead of Seirin. Akashi, as the captain, is initially skeptical but soon realizes her potential. They start training together intensively. As they do so, they begin to develop feelings for each other. However, they face opposition from some of the team members who are not used to the idea of their captain being involved with a female teammate. But through their strong bond and love for basketball, they overcome these obstacles and their relationship blossoms.
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.
The kidnappers could be motivated by jealousy. They might see Kuroko's skills and his importance to Seirin and want to take him out of the picture so their own team can have an advantage. For example, a rival team that has been losing to Seirin might think that without Kuroko, Seirin will be easier to defeat.