A common plot point is Tonks arriving just in time. For example, Harry might be surrounded by Death Eaters, and Tonks shows up out of nowhere, using her combat skills and magic to fend them off. Another is Tonks using her Metamorphmagus ability to deceive the enemy. She could transform into a Death Eater to get close to Harry when he's held captive. Also, often Tonks has to overcome some sort of obstacle or enemy plan before she can save Harry, like breaking through a magical barrier that was set up to keep her away from Harry.
There are some 'Tonks Saves Harry' fanfics out there that are really interesting. In some of them, Tonks saves Harry from a dangerous spell that was cast on him. She might have to use her knowledge of advanced magic to counter the spell. In other cases, Tonks saves Harry from a situation where he's about to be captured by Voldemort's forces. She could be on a secret mission and stumbles upon Harry in trouble. Her quick thinking and her loyalty to Harry lead her to take risks and ultimately save him.
One common theme is friendship. Writers often explore how these three very different characters form a strong bond. Another theme is adventure. They usually go on various quests or face dangerous situations together. For example, in many fanfics, they might be on a mission to save Hogwarts from a new dark threat.
One common theme is friendship. Since they are both part of the wizarding world, fanfics often explore how they become friends and support each other. Another theme could be adventure, as they might go on quests together or face dangerous situations side by side.
One common plot element is the initial conflict or danger that Harry is in which Blaise has to save him from. It could be a Death Eater attack or a dangerous spell gone wrong. Then there's the part where they start to get to know each other better after the rescue. Often, there's some sort of misunderstanding or resistance from either Harry or Blaise due to their different house backgrounds, but they eventually overcome it.
One common plot point is that Harry often has to find a way to get past the Dementors in Azkaban. He might use the Patronus charm in a new and creative way. Another is that he usually has to overcome some sort of magical obstacle or security measure in the prison. And of course, there's always the emotional reunion between Harry and Sirius.
Often, these fanfics deal with the theme of changing destinies. In the original story, Harry and Tonks' paths are quite different. But in these fanfics, their relationship can change the course of their individual fates. For example, they might have to face opposition from the wizarding community which then becomes a part of the story's conflict. Also, the theme of emotional growth is present. As they navigate their relationship, they learn to deal with complex emotions like love, jealousy, and loyalty.
A common plot point is the confusion and disorientation of Harry. He often doesn't recognize his friends or the Hogwarts environment. For example, in many fanfics, he might stare at the Great Hall as if he's seeing it for the first time.
One common plot point is the emotional reunion between Harry and his parents. There's often a lot of crying and hugging. Another is how Harry's parents deal with the people who abused Harry. They might seek revenge or at least make sure those people can't harm Harry again.
Often, a common plot point is their interaction within the Order of the Phoenix. For example, Tonks might be assigned to protect Harry, leading to some tense and exciting moments as they face threats together.
One common theme is adventure. Given their characters in the original series, fanfic writers often put Tonks and Harry on new adventures together, fighting new threats or exploring new magical places.