Another plot could be the apprentice getting involved in a time - traveling adventure. They might travel back in time to witness key events in the wizarding world's history, like the founding of Hogwarts. Along the way, they could accidentally change something in the past, and then have to find a way to fix it before it causes chaos in the present.
It could also be a character from outside of Hogwarts. Maybe a young wizard who has been self - taught in some dark magic and Dumbledore takes them as an apprentice to guide them towards the light side of magic. Dumbledore would see the potential for good in this character and want to reform them.
Ron could also be there. He might be a bit jealous at first of Harry's special relationship with Dumbledore but then comes around and supports Harry in his adventures as an apprentice. There could be some great scenes of their friendship evolving in this new context.
In some fanfictions, Harry as Dumbledore's apprentice might have to deal with a dark prophecy that only he, with Dumbledore's guidance, can solve. This could lead to a journey where he has to make difficult choices between different paths, each with its own consequences for the wizarding community. It would be a great exploration of Harry's character growth and his relationship with Dumbledore in a more in - depth and unique context.
Harry may also develop a greater sense of responsibility. Knowing that Dumbledore has chosen him as an apprentice implies a certain level of trust and importance. He would feel the need to live up to Dumbledore's expectations and use his new - found knowledge and skills to protect the wizarding world. He could start to take on more leadership roles and be more proactive in the fight against the dark forces.
One possible fanfic could be about Harry Potter starting his apprenticeship at Gringotts and uncovering secrets about the bank's vaults. He might learn about the magical security systems and the history of some of the most powerful magical artifacts stored there.
One interesting plotline could be Harry learning advanced magic from Dumbledore that is not taught in the regular Hogwarts curriculum. For example, he might learn ancient spells for protection or divination techniques that are long forgotten.
Perhaps the fanfic's plot involves a character who is unknowingly Merlin's apprentice. They start having strange dreams about Merlin guiding them. As they explore these dreams, they learn skills like time - traveling magic which Merlin was known for. They then use this ability to go back in time and change certain events in the wizarding world's history for the better, all while trying to keep it a secret from the other Hogwarts students and faculty.
It could be that Harry finds out about Dumbledore's secrets regarding the Deathly Hallows. If Harry thinks Dumbledore was more interested in the Hallows for his own purposes rather than for the greater good, it might make him hate Dumbledore.
In the 'Harry Potter' fandom, this would be a very controversial concept. Dumbledore is often seen as a mentor and a powerful, positive figure. Having Harry Potter destroy him goes against the general perception of their relationship in the original series. However, in the realm of fanfic, some might explore such a dark and alternative take as a way to examine different character arcs and what - if scenarios, but it would likely be met with a lot of resistance from purist fans.