In some fanfictions, a great plot twist is when Draco is on the verge of making a really bad decision, like joining the Death Eaters completely. But then he discovers his true relation to Severus. This changes his perspective as he realizes Severus has been secretly protecting him all along. It makes him question his loyalty to the Dark side. Also, there could be a plot twist where Severus has to choose between his loyalty to Dumbledore and protecting his son Draco, which creates a lot of internal conflict for him.
One interesting plot twist could be that Severus and Harry are forced to marry for political reasons in the wizarding world. Maybe there's a threat from a dark force and their union is seen as a way to unite different factions. Another could be that they initially hate the idea but gradually fall in love as they discover things about each other they never knew. For example, Harry might learn about Severus's deep - seated loyalty to Dumbledore and Severus might see Harry's strength beyond his Gryffindor bravado.
In some of these fanfictions, a great plot twist is that Draco, being a Muggleborn, is actually a long - lost heir to a powerful Muggle - related magical artifact or prophecy. This throws the whole wizarding world into chaos as different factions try to either use him or protect him. Also, there could be a plot twist where Draco uses his knowledge of the Muggle world to outwit dark wizards. Since he has a connection to the Muggle world that most pure - bloods don't, he can come up with strategies that are completely unexpected, like using Muggle technology in a magical way to defeat his enemies.
Perhaps in the fanfiction, Draco Malfoy turns out to be a double agent. He pretends to be on the side of the Death Eaters like his family, but in reality, he is secretly helping Harry Potter and the Order of the Phoenix. Snape discovers this and has to decide whether to expose Draco or use his secret to their advantage. This would create a lot of tension and unexpected alliances.
In some fanfictions, a cool plot twist could be that Percy's connection to Kronos gives him the ability to travel through time. He could use this power to go back and change certain events that led to Kronos' rise or fall. But this also comes with risks, like accidentally changing things for the worse or getting trapped in a different time period.
In some of these fanfictions, a great plot twist is when Hermione gets cursed and Draco has to find a way to break it. During this process, they learn more about each other's true selves. Also, it could be that Draco is under the influence of a dark spell that makes him act against Hermione, but she believes in the good in him and tries to break the spell, which deepens their bond in a very unexpected way.
Well, in some fanfictions, a plot twist might be that Draco and Harry are forced to marry by a magical contract that was hidden for ages. And as they try to break it, they actually fall in love. Or perhaps a twist where Draco is actually a spy for the good side all along and their marriage is part of a grand plan to expose the remaining Death Eaters. There could also be a twist where Harry loses his memory and Draco has to make him fall in love with him all over again while dealing with the wizarding world's reaction to their union.
One interesting plot twist could be that the fourth hokage didn't actually die when he sealed the nine - tails in Naruto. Instead, he was trapped in a sort of limbo within Naruto's mind and could communicate with him at crucial moments, guiding him in ways that no one else could understand.
One interesting plot twist could be that Draco has some hidden knowledge about the Horcruxes from his family's dark secrets. Maybe his mother had unknowingly passed on some crucial information to him that helps Harry and him in a very unexpected way during the hunt.
One idea could be a story where Harry, Draco, and Severus are forced to work together on a dangerous mission to save Hogwarts from a new dark threat. They start off distrusting each other but gradually learn to respect and rely on one another.
Perhaps a plot twist where Draco sacrifices himself for the Golden Trio. In a moment of danger, instead of saving himself as one might expect from his Slytherin self - preservation instincts, he chooses to protect his new friends. This would be a huge shock and a great development in the story of their friendship. It could also lead to the Trio then finding a way to bring Draco back to life, which would be another interesting turn in the plot.