Well, there are fanfictions where the plot twist is that Voldemort and Harry end up having to team up. Perhaps there is an even greater evil emerging that forces them to put aside their differences. This completely changes the dynamic of their relationship. Additionally, some fanfictions might have a twist where Harry is actually transported to an alternate dimension during the battle, and he has to find his way back and face Voldemort in a completely different setting, which adds a whole new layer of complexity to the story.
One interesting plot twist could be that Voldemort actually has a change of heart. Maybe in the fanfiction, he realizes the futility of his dark ways after seeing the strength of Harry's love and friendship. Another could be that Harry discovers a new, unexpected power within himself that is not related to his typical Gryffindor courage or his connection to Voldemort's soul pieces. For example, he might find he has the ability to manipulate time in a way that gives him an edge in the battle.
In some fanfictions, a plot twist might be that the Hogwarts itself becomes an active participant in the Harry vs Voldemort battle. The castle could use its magic to protect Harry or even to hold Voldemort at bay. Also, there could be a twist where a minor character from Hogwarts, like a house - elf or a rarely - mentioned student, has a hidden power that they use to turn the tide of the battle. It makes the story more exciting as it gives a new perspective and new forces to the well - known battle.
Chapter 234, "Chasing Wind Youth", is the clearest early answer because it turns Good's situation into a concrete plot event. The chapter turns that into something concrete by moving from Given the vast mystical powers Jiang Li had displayed before, he was...
Chapter 266, "He Really Deserves to Die!", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. The chapter turns that into something concrete by moving from Upon hearing this, the deputy director's expression also turned...
Chapter 112, "The Strange "Team Spirit" Appears", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. It opens with These five people are supposed to be at odds.
Chapter 19, "I dare you to touch her!", is the clearest early answer because it turns Shang's situation into a concrete plot event. A useful checkpoint is the way the scene starts with What criminal law is this or that, this was originally none of your...
Chapter 335, "Songyang Ridge, Seven Houses Surrender, First Batch of Silver Arrives", is the clearest early answer because it pushes Nie Zichuan into a new phase or setting. The chapter turns that into something concrete by moving from The name "Songyang Ridge" was not given by Xu Ning; he discovered... to Ji Yang from Wanlong, representing the Six Families of Songyang....
Chapter 155, "There Are Actually Two Flying Guests?!", is the clearest early answer because it turns Live Variety's situation into a concrete plot event.
Chapter 37, "Those in the know anticipate the transformation, while the oblivious think it's a fashion show.", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.
Chapter 489, "Has She Been Morally Kidnapped?", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter gives readers a real answer by opening on Yeah," Nina nodded, "I thought you looked pretty imposing, must be...
Chapter 3, "Madam, the eldest young master has been missing for over half a month", is the clearest early answer because it turns Qiao's situation into a concrete plot event.
Chapter 89, "Brother He, how can you be so unreasonable too?!", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event.