Perhaps they are the only Animagus in their generation. Their forms could be a phoenix and a fox respectively. The story could revolve around how they have to keep their Animagus status a secret from everyone, including their friends, because there is a dark force that is hunting down Animagus. And they must use their forms to outwit this dark force and protect their loved ones. This would involve a lot of mystery, adventure, and some really cool scenes of them transforming and using their animal instincts.
A great plot idea is that their Animagus forms are linked in some way. For example, Ginny's Animagus form is a small bird and Harry's is a large eagle. Harry has to protect Ginny in the wizarding world, but in their Animagus forms, it's the other way around. Ginny's small bird form can access places that Harry's eagle form can't, and she uses this to gather information. The story could be about their growth as Animagus and as a couple, as they learn to work together in both human and animal forms.
One plot idea could be that Harry and Ginny discover they are Animagus during their time at Hogwarts and use their forms to secretly explore the Forbidden Forest. Their Animagus forms might give them an advantage in finding hidden magical creatures or ancient magic that could help in the fight against Voldemort.
One idea could be Harry discovers he's an Animagus early on, perhaps in his second year. He turns into a stag like his father and uses this form to explore the Forbidden Forest secretly. Another could be that he has to hide his Animagus form from the Ministry which is on high alert for unregistered Animagi.
A plot could be that a Gryffindor Animagus accidentally reveals their form during a Quidditch match. This causes chaos as everyone tries to figure out who it is. It also draws the attention of the Ministry of Magic who have strict rules about unregistered Animagi. The character then has to deal with the consequences while also trying to prove they mean no harm.
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.
One idea could be exploring how they adjust to the news. Maybe Ginny has to cut back on her Quidditch training, and they deal with the excitement and nervousness of impending parenthood. Another plot could involve them sharing the news with their friends and family, like Ron's hilarious reactions.
Another interesting plot could be that Harry's transformation into a Black Lion is a sign that he has a deeper connection to Salazar Slytherin than anyone thought. It turns out that Slytherin had an affinity for lions in a different way than Gryffindors. This discovery causes a stir in the wizarding world, and Harry has to deal with both the prejudice and the new opportunities that come with this revelation. He could use his newfound connection to Slytherin's legacy to bring together the houses in a way that has never been done before in the fight against the Dark Lord.