A possible plotline could revolve around the technology or magic behind Harry's prosthetics. The fanfic could explore how the prosthetic limbs and eye were created. Were they made by a combination of Muggle technology and wizarding magic? Or perhaps it was an ancient, forgotten magic that was rediscovered to create these prosthetics. The story could also focus on Harry's emotional state. He could initially feel self - conscious about his new body parts but gradually grow to be proud of them as he realizes they make him stronger in a way.
It could be a dark wizard who sees Harry's new prosthetics as a source of power. Maybe this dark wizard wants to steal the magic or technology behind the prosthetics to use for his own evil purposes. For example, he might believe that the prosthetic eye holds a special power that could help him see into the future or find hidden treasures.
One possible plotline could be that Naruto gets an eye transplanted from an Uchiha. This new eye might give him the ability to use Sharingan techniques. He could struggle at first to control it, like Sasuke did when he first awakened his Sharingan. It might also change his perception of the ninja world, as he now has a power that was once exclusive to the Uchiha clan.
One possible plotline could be that Harry got injured during a battle against a dark wizard, resulting in the loss of an eye. He then has to adapt to his new situation while still facing the challenges in the wizarding world. For example, he might struggle with his depth perception during duels.
In the fanfic, it might be set in an alternate universe where Sakura has a different personality. She could be more aggressive and competitive with Naruto. During a sparring match, she goes too far and seriously hurts Naruto. This could then be the starting point of a story about Naruto having to forgive her and them rebuilding their friendship.
Perhaps Harry witnesses Snape being extremely unfair to a group of students, like constantly giving them detention for no good reason. Harry decides to take a stand and gathers statements from the students. He then goes to the Hogwarts board of governors and presents his case, leading to Snape's dismissal.
"Attract Your Heart" and "Marriage Is Like a Cocoon, Love Is Bound to You" were two modern romance/urban novels. The female lead in the story wore a prosthetic leg. These two novels could be recommended to readers who liked modern novels and paid attention to the female protagonist's use of prosthetic equipment.
One possible plotline could be that Harry realizes the wizarding world has some deep - seated flaws that Voldemort also wants to change. So, they form an alliance to reform the Ministry of Magic. For example, they might work together to end the pure - blood supremacy that has long plagued the wizarding society.
Perhaps Grindelwald teaches Harry about the history of magic in a very different way than what Harry has learned before. He might show Harry the secrets of magic that have been hidden by the wizarding world's authorities. This could lead Harry to question the existing order and his own beliefs. Maybe Harry starts to see the gray areas in the battle between good and evil.
One possible plotline could be that Professor Riddle, perhaps a relative of the infamous Voldemort (Tom Riddle), initially has a strained relationship with Harry. He might be suspicious of Harry due to his family connection to the Potters. However, as the story progresses, they could discover they have more in common than they thought, like a shared interest in some arcane magic. And they might end up working together to solve a mystery within Hogwarts that threatens the entire wizarding world.
One possible plotline could be Bellatrix trying to mold Harry into a dark wizard. She might use her knowledge of the Dark Arts to teach him, but Harry resists. Another could be that Bellatrix starts to have a change of heart while raising Harry and begins to question her loyalty to Voldemort. Maybe she sees something in Harry that reminds her of a better part of herself.