One interesting plotline could be exploring their early days at Hogwarts together. Maybe they were both brilliant students with different outlooks that gradually diverged. Another could be a story where they meet again after Dumbledore defeats Grindelwald, and there are still unresolved feelings and thoughts between them. A third one might be a fanfiction that delves into an alternate universe where they actually work together to achieve some 'greater good' that they both misinterpreted in different ways.
Some plotlines involve their relationship before it turned sour. For instance, a story might show how they discovered magic together in their youth, traveling to hidden magical places and sharing their knowledge. Or it could be about how Grindelwald influenced Dumbledore's views on wizard - muggle relations in a more complex way than just pure evil. Also, there could be a plot where Dumbledore tries to redeem Grindelwald through magical means rather than just imprisoning him, exploring the power of love and forgiveness in the wizarding world.
One interesting plotline could be Harry somehow traveling back in time to meet Grindelwald in his prime. This could lead to a battle of wits between them, with Harry trying to stop Grindelwald from starting some of his more heinous plans early. Another might be that Grindelwald, seeing Harry's power, tries to recruit him to his side, offering him power and knowledge that Harry has to resist.
One interesting plotline could be exploring Dumbledore's younger years through Harry's eyes. Maybe Harry discovers some old memories of Dumbledore's adventures as a young wizard, and it helps him understand Dumbledore better. This could also show how Dumbledore's past experiences shaped his decisions in dealing with Harry and the fight against Voldemort.
Aberforth Dumbledore can be a very important character in these fanfictions. He is Albus Dumbledore's brother and has his own feelings and history related to his brother and Grindelwald. He might be the one who tries to bring his brother back from the brink when Dumbledore is too involved with Grindelwald. Also, Leta Lestrange could be popular. Her family's dark reputation and her own complex relationship with Newt and the wizarding world in general can add an extra layer of drama to the fanfictions involving Dumbledore and Grindelwald.
One possible plotline could be Harry's internal struggle with his heritage. Since Grindelwald was a dark wizard, Harry might battle with the idea of having such a connection. He could face prejudice from the wizarding world while also trying to understand if there are any redeeming qualities in Grindelwald's ideology that might be passed on to him.
In some fanfictions, there could be a plotline where Harry Potter discovers a hidden connection between himself and Grindelwald. Maybe through some ancient magic or a family secret. This connection then leads to a series of events where they must interact and understand each other better. For example, they might have to exchange magical knowledge to solve a mystery that is plaguing the wizarding community. Or perhaps Harry has to enter Grindelwald's mind to find a way to defeat a common enemy, which is a very mind - bending and exciting plot.
One interesting plotline could be how Dumbledore helps Harry discover his true magical potential beyond what he learned at Hogwarts. For example, he might introduce Harry to ancient and rare magic that was long forgotten. Another could be Harry's relationship with the wizarding community changing as he is now seen as Dumbledore's adopted son. This could lead to new friendships and alliances. Also, Dumbledore might train Harry to become a great leader in the wizarding world, preparing him for future threats that are much larger than Voldemort.
One possible plotline could be Dumbledore being judged for his actions regarding Harry Potter. For example, some fans might write about how his decisions to keep certain secrets from Harry were either right or wrong. Another could be his past associations being put under the microscope, like his relationship with Grindelwald.
One interesting plotline could be exploring Dumbledore's family history in more depth through Harry's perspective. For example, how Dumbledore's past actions and family relationships might influence Harry's journey. Another could be a story where Harry discovers a long - lost relative who was also connected to Dumbledore's family. This could add a whole new dimension to the wizarding world he thought he knew.
Well, it could be that Dumbledore has some sort of hidden device or spell that he activates when kidnapped. For example, he could have a charmed object that sends a signal to his allies, like the Order of the Phoenix. His allies then come to his rescue and he manages to escape during the chaos. Also, Dumbledore is extremely intelligent. He might outwit Grindelwald by engaging him in a complex conversation full of riddles and misdirections, which gives him an opportunity to break free.
Plots that involve Grindelwald's unorthodox magical experiments are really captivating. In 'Grindelwald's Forbidden Magic', the fanfic shows how his experiments could have changed the wizarding world if they had been fully realized. It's full of mystery and danger.