What could be the plot of a 'Harry Potter trained by Grindelwald' fanfiction?

One possible plotline could be Harry initially being forced into the training but then gradually getting intrigued by Grindelwald's knowledge. He might start to question the traditional teachings of Hogwarts. Another could be that Harry is tricked into the training, thinking Grindelwald has good intentions only to discover the truth later.

Well, it depends on what you consider 'good'. Some people might like the ones that focus on Harry's internal struggle while being trained by Grindelwald. For example, there could be fanfictions where Harry has to decide whether to follow Grindelwald's teachings or stick to his own values. However, not all such fanfictions are well - written. Some might have plot holes or out - of - character moments.

One possibility is that Harry discovers a world where fanfiction has the power to change the real wizarding world. So he has to train to fight against the alterations caused by these fictional stories. For example, if a fanfiction made Hogwarts a place full of dangerous magical beasts that don't belong there, Harry would need to train to restore order.

Well, perhaps Harry could be trained in some long - lost or dark magic that Dumbledore has been hiding from him. This new training might make him even more powerful than before, able to defeat Voldemort in a more spectacular way.

Maybe Harry discovers some long - lost magic techniques taught by Godric. He could become super powerful and use ancient spells to fight Voldemort.

Well, in this fanfiction, it could be that Hephaestus trains Harry Potter to have a better understanding of the more physical and mechanical aspects of magic. For example, he might learn to build magical devices that can be used in battles or for other important tasks. This would give Harry an edge over his enemies as he'd have skills that no other wizard has. It could also lead to new alliances as other wizards might be interested in his newfound abilities.

Well, perhaps in this fanfiction, Harry discovers he has an affinity for snakes early on. Maybe he's able to communicate with them in a deeper way than Parseltongue allows. The snakes could train him in stealth and survival skills, like how to move quietly in the Forbidden Forest or find hidden passages. They could also teach him some unique magic that is related to the ancient magic of serpents.

Maybe it's about Harry learning some advanced magic spells from Flitwick. Flitwick could be teaching Harry unique charms or how to use his wand more effectively.

It could be that the SAS trains Harry Potter in modern warfare tactics. This would be a really interesting twist as he could combine magic with these new skills. He might learn how to use firearms in a Muggle - like way, but then enhance them with magic for more power and accuracy.

Well, perhaps in this fanfiction, Harry could be secretly trained by an ancient and powerful wizard who has been in hiding. This wizard might teach Harry some long - lost magic spells and combat techniques that are far more advanced than what he learned at Hogwarts. It could also involve Harry having to keep this training a secret from his friends and teachers, adding an element of mystery to the story.