One popular plotline could be Harry traveling back in time to prevent certain tragedies in Tonks' life. For example, he might try to stop her from being killed in the Battle of Hogwarts. Another could be Tonks traveling to a time in Harry's past to offer her unique magical abilities to help him in his early struggles against Voldemort. And sometimes, they both might travel back to a crucial moment in wizarding history to change the course of events that led to Voldemort's rise in the first place.
One popular plotline is Harry going back in time to change key events in the wizarding world. For example, he might go back to prevent certain deaths like Sirius Black's. Another could be him traveling to the past to gain more knowledge about magic from the great wizards of old, which he then uses to fight Voldemort more effectively in his own time.
A possible plot is that Harry and Tonks time travel to a point where the creation of Horcruxes was just beginning. They could try to stop Voldemort from splitting his soul, which would change the whole course of the wizarding world's history. They would face many challenges, like not being discovered by Voldemort or his followers. Also, Tonks might use her skills to distract or mislead some of the Death Eaters while Harry looks for a way to destroy the Horcrux - making materials or the places where Voldemort hid them.
One possible plotline could be Harry and Tonks teaming up with the members of the harem to face a new dark wizard threat. They might use their combined magical abilities and unique relationships to outwit the enemy.
One possible plotline could be how Harry and Tonks navigate their different personalities. Harry is often seen as serious and determined, while Tonks is more carefree and fun - loving. Their relationship might start with some misunderstandings due to these differences but then grow into a deep understanding and love. Another plotline could involve how they deal with the wizarding world's reaction to their union, as it's quite an unexpected pairing. Some might oppose it, while others might see it as a new beginning for the wizarding community.
One interesting plotline could be how they deal with the challenges of their different personalities. Harry is often seen as serious and determined, while Tonks is more carefree and fun - loving. Their marriage might involve a lot of humorous misunderstandings at first as they learn to live together. For example, Tonks might play pranks on Harry that he initially doesn't take well but then learns to enjoy.
One interesting plotline could be Harry and Tonks teaming up for a secret mission in the wizarding world that was not part of the original story. Maybe they have to infiltrate a dark wizard's lair.
One popular plotline is Kirito traveling back to the beginning of SAO. He could use his knowledge from the first play - through to change things for the better, like saving more players from the start. Maybe he'd find a way to defeat the bosses more easily or prevent certain in - game tragedies.
Time travel for Harry could be a way to confront his past traumas. He might go back to a time when his parents were alive and get some closure. This could make him more at peace with himself and less haunted by his past. As for Tonks, time travel could expose her to different forms of magic and different social structures. If she travels to a time when pure - blood - supremacist ideas were more prevalent, she could become more of an advocate for equality. She might also see how her family has evolved over time, which could give her a stronger sense of identity and purpose.
It might also be time itself. There could be some sort of time - related magic or force that doesn't want the past to be changed. So Harry and Tonks would have to face this 'antagonist' as they try to rewrite history. This could be in the form of time - locked spells or magical barriers that prevent them from interfering in certain events.
One interesting plotline could be about Tonks facing the challenges of being pregnant during a time of great turmoil in the wizarding world. Maybe she has to hide her pregnancy to protect herself and the unborn child from the dark forces. Another could be how her relationship with other characters, like Lupin, evolves during her pregnancy, as they deal with the prejudices against werewolves and the danger that surrounds them.