Well, it could be about Harry and Ginny starting a Quidditch club for the underprivileged wizarding kids in the Muggle - born areas. They would have to overcome the prejudices of some pure - blood families who don't think Muggle - borns should play Quidditch. Also, they could be involved in a plot where a magical object that enhances Quidditch skills is stolen, and they are on the hunt to find it and return it to its rightful place so that the fairness of the game is maintained.
A possible plot is that there's a mysterious illness spreading among the Quidditch players, and Harry and Ginny have to figure out what's causing it and how to stop it before the big Quidditch tournament. Or perhaps a new and dangerous Quidditch move is introduced by a visiting team, and Harry and Ginny must learn it quickly to stay competitive. They could also have a friendly rivalry with another couple who are also big Quidditch fans.
Perhaps there's a magical guitar that Harry and Ginny find. It has special powers, like when Ginny plays it, it can calm the most ferocious magical creatures. They go on a journey to figure out the origin of the guitar and along the way, their relationship deepens as they face various challenges together.
One idea could be that Harry and Ginny are swimming in a secret pool at Hogwarts that has some magical properties. Maybe the pool can change its shape or temperature based on their emotions. Another could be that they are having a swimming race to train for a Triwizard Tournament - like event for adults. And they use magic to enhance their swimming abilities in creative ways.
One idea could be a story about a new Quidditch team formed by students from different houses. They face challenges not only on the pitch but also in terms of getting along with their diverse teammates.
Another plot could revolve around a conspiracy to fix the Quidditch World Cup results. A group of dark wizards might try to influence the outcome for their own gain, like betting on a certain team to lose. A young wizard or witch who discovers this plot then has to find a way to expose it and save the integrity of the tournament.
One plot idea could be that Hermione and Ginny team up to play a prank on Harry, but it backfires in a hilarious way. For example, they try to make his hair turn purple but instead it starts changing colors every few seconds. Another idea is that the three of them go on a secret adventure outside of Hogwarts to find a lost magical artifact. They face various challenges and their friendship is tested. And perhaps a plot where Hermione discovers a new spell that accidentally causes some chaos between Ginny and Harry's relationship, and she has to find a way to fix it.
One idea could be exploring their wedding planning and all the chaos that comes with it. Maybe Molly Weasley is over - involved and wants everything to be perfect, while Ginny just wants a simple ceremony. Another could be their first year of marriage, dealing with things like living together in a new home and adjusting to each other's habits.
In a 'Harry Marries Ginny' fanfiction, a great plot could be about them starting a family. It could detail Ginny's pregnancy, Harry's concerns and excitement, and how they prepare for the arrival of their baby. It could also include the reactions of their friends and family. This would be a heart - warming story that shows their growth as individuals and as a couple.
One idea could be that Harry returns from a long and dangerous mission. Ginny has been worried sick. When they reunite, there's an immediate rush of emotions. They hug tightly and Ginny scolds Harry a bit for making her worry, but it's all out of love. Another could be they reunite at Hogwarts during an anniversary event. They see each other across the Great Hall and slowly make their way towards one another, with memories of their school days flooding back.
Perhaps Teddy gets into trouble at Hogwarts, and Harry and Ginny have to step in to sort things out. It could involve Teddy being wrongly accused of something, and they use their skills and influence to clear his name. Or Teddy discovers a secret room in Hogwarts that only he can access, and he enlists Harry and Ginny to explore it with him.
One idea could be how Harry and Ginny prepare for the baby, like choosing names. Another might be Ginny's experience with the physical changes during pregnancy. Maybe there could be a plot where they face some threats while Ginny is pregnant and Harry has to protect her and their unborn child.