Another concept could be centered around the characters' reactions when they finally locate the seventh horcrux. There could be internal struggles among the characters, like Harry having doubts about whether destroying it is the right thing to do, considering it might hold some knowledge that could be useful against Voldemort.
In many fanfictions, Neville Longbottom might also play a significant role. He has grown into a powerful wizard by this point in the story. His knowledge of Hogwarts and its secrets could be crucial in the search for the seventh horcrux. He could be the one who discovers a hidden passage that leads to the location of the horcrux.
Yes, in some fanfiction, Harry Potter is considered a Horcrux. This concept adds an interesting twist to the original story, exploring different aspects of magic and the connection between Harry and Voldemort.
One consequence could be that his connection to Voldemort becomes even stronger. This might lead to him being able to sense Voldemort's actions and thoughts more clearly, but also make him more vulnerable to Voldemort's attacks on his mind. Since the Horcrux is a part of Voldemort's soul, it could also start to influence Harry's personality, making him more aggressive or moody at times.
If Harry were to create a Horcrux in fanfiction, it would likely lead to a great corruption of his soul. Horcruxes are dark magic, and the act goes against all that Harry stands for in the original series. He might start to show signs of increased aggression, a detachment from his friends, and a growing attraction to the Dark Arts.
Well, in some fanfictions, a Horcrux might be purified through powerful magic spells that are specifically created for the purpose. For example, a spell that can reverse the dark magic used to create the Horcrux in the first place.
Well, it could be that Dumbledore, in some fanfic versions, figures it out first and then reveals it to Harry. Dumbledore is often portrayed as having a deep understanding of magic. He might have noticed some strange magical patterns or behaviors related to Harry that led him to suspect and then confirm that Harry was a Horcrux. And then he would tell Harry about it, which is how Harry comes to know.
Perhaps his father's old wand. It has a connection to his family and his heritage. Since it's a wand, it already has a certain amount of magical energy, so it could potentially be a suitable vessel for a Horcrux. And it would be a very interesting twist on the concept of a Horcrux as wands are not a typical choice.
One consequence could be that Harry feels an internal struggle. Since he has a part of Voldemort's soul in him, he might have to constantly fight against the dark impulses that come with it. For example, he may find himself having more aggressive thoughts or being more easily influenced by dark magic in certain situations.