Well, in this type of fanfiction, a plot could be that Harry is forced to be a baby due to a dark magic experiment gone wrong. As a baby, he may start to show signs of his future heroic self in unexpected ways. For instance, he might be able to communicate with magical creatures that are drawn to his innocent form. Also, Dumbledore could be faced with a new challenge of protecting Harry in this vulnerable state. He might have to place Harry in a different kind of hiding, perhaps with a family that has special abilities to deal with magically altered children.
Some fanfictions in 'Harry Potter Forced Marriage' have a plot where Voldemort, in an alternate scenario where he didn't die, forces Harry to marry one of his loyal followers. This creates a really complex situation for Harry. He has to not only deal with the idea of being married to someone he doesn't love but also figure out a way to use this situation against Voldemort. It could involve him trying to turn the follower against Voldemort or find a loophole in the forced marriage magic.
Well, in some versions of such fanfiction, Harry as a girl might have a different relationship with the teachers. The teachers might treat her differently, like McGonagall perhaps being more protective or having different expectations. Also, the way Harry (as a girl) interacts with Voldemort could be really unique. Voldemort might underestimate her because of her new gender identity, but she could use that to her advantage in battles.
One possible interesting plot could be Harry's internal struggle with being forced into the Triwizard Tournament. He might have to deal with the pressure of competing while also trying to figure out who or what is behind this forced entry. Another plot could involve how his relationships with Ron and Hermione change due to this unexpected situation. Maybe Ron becomes jealous at first because Harry gets all the attention, but then they reconcile as they realize it's not Harry's fault.
In some fanfictions, it could be a plot device used in a time - travel scenario. Harry is sent back in time and for some reason, he is forced to touch a younger version of a character. This could be Dumbledore as a young wizard. The touch might be forced by a temporal anomaly or a spell set by a time - traveling antagonist. This forced touch could then have a profound impact on the timeline, causing changes in the future that Harry has to deal with. It could also lead to a deeper understanding of the character's past and how it shapes their future actions.
Perhaps in the fanfiction, Harry is magically bound to please Snape in academic tasks. So, he has to study extra hard in Potions class and other subjects Snape is involved in. This might result in a transformation of their relationship, from animosity to a grudging respect as Snape starts to see Harry's efforts.
One possible interesting plot could be Harry's internal struggle. He might be conflicted between his sense of duty in this forced marriage and his true feelings for Ginny. Maybe at first he resists, but as time goes by, he starts to discover new sides of Ginny that he hadn't noticed before, leading to a gradual development of real feelings.
In some Harry Potter 8 fanfictions, there are plots where the characters continue to face new dark magic threats. For example, a new dark wizard might emerge, and Harry, Hermione and Ron have to use their combined skills and knowledge to defeat this new foe. Another plot could be about the exploration of the wizarding world's past in more depth, revealing secrets that were previously unknown.
In some fanfictions, the forced marriage could lead to a situation where Harry and Severus have to protect each other from external threats. Harry's status as 'The Boy Who Lived' makes him a target, and Severus's past associations also put him in danger. As they face these threats together, they start to rely on each other. This mutual reliance then turns into a deeper emotional connection.
Well, one plot could be that Harry is adopted by a family outside of the wizarding world. He grows up with no knowledge of magic until strange things start to happen around him. Then he discovers his true heritage.
Maybe the story could revolve around how Harry and Luna protect their baby from dark forces that still lurk in the wizarding world. They would use their unique skills and knowledge to keep the baby safe. For example, Luna's ability to see things others can't might help them detect hidden threats. Harry, with his combat skills, would be ready to fight off any attackers. Their friends like Ron and Hermione could also play important roles in this story, perhaps helping to babysit or providing magical protection for the baby.