One possible plot could be that they sing to cheer up their friends at Hogwarts during a difficult time, like after a battle or when everyone is feeling down because of exams. Their singing could have some magical effect that lifts the spirits of those around them.
Yes, there might be some. Fanfiction websites like Archive of Our Own (AO3) or FanFiction.net could potentially have such stories where Harry and Hermione sing. You can search for relevant tags like 'Harry Potter', 'Harry', 'Hermione' and'singing' on these platforms to find them.
In the fanfiction, Luna might be lost in a time - loop created by a malfunctioning time - turner. Hermione realizes what has happened due to her familiarity with time - turner magic. Harry goes with her to enter the time - loop. Inside, they face various challenges from different time periods. They find Luna, who has been trying to break the loop on her own. The three of them then work together. Hermione figures out the correct sequence of spells, Harry provides the necessary distraction to the time - loop's guardians, and Luna uses her natural connection to magic to help Hermione complete the spell that breaks the loop.
Perhaps in the fanfiction, Harry and Hermione raise a child who has a connection to a long - forgotten dark magic. They have to protect the child from those who would use the child's power for evil. Along the way, they face challenges in the wizarding world where some people are suspicious of their decision to raise this special child. But they stand strong, using their combined knowledge and skills to keep the child safe and raise it with good values.
One possible plot could be that they are in a magical pool area. Hermione has a special bikini that has some magical properties. When Harry sees her in it, he is intrigued. As the story progresses, they might get involved in some sort of magical adventure related to the bikini, like it being a key to an underwater magical realm. Along the way, their relationship could develop further, whether it be a stronger friendship or the start of a romantic relationship.
One possible plot could be that they move to America to start a new life away from the wizarding war in Britain. They might discover new magical communities in America, like Ilvermorny, and get involved in protecting its secrets. Maybe they meet new friends and enemies along the way and use their combined skills from Hogwarts to face new challenges in this different magical environment.
Well, it could be about their continued adventures in the wizarding world. Maybe they are working together on some new spells or dealing with a new dark force that has emerged. They might also be mentoring the new generation of wizards at Hogwarts.
Well, perhaps in the fanfiction, Harry and Hermione teach the Marauders advanced magic that they themselves have learned in their own time. For example, Hermione could teach Remus some new spells for defense against the dark arts, and Harry could show James some Quidditch techniques that he developed later. They could also try to change the Marauders' view on Snape, trying to prevent some of the animosity that developed between them.
One plot idea could be that they use magic to transport themselves to Panthers games and have to keep it a secret from the wizarding world. Another could be that they meet other Panther fans in the wizarding world and form a secret fan club.
It could be that Ron and Hermione abandon Harry due to a prophecy that they misinterpret. They believe that by being with Harry, they will bring doom to the wizarding world. So they go into hiding. Harry, on the other hand, is determined to change the course of the prophecy. He embarks on a journey to find the truth behind it, all while feeling the pain of his friends' desertion. He has to fight against dark forces that are taking advantage of the situation.
One possible plot could be that Harry and Hermione, after their adventures at Hogwarts, realize their deep connection. They get married and start a family. Their children could inherit unique magical abilities from both of them. Maybe one child has Harry's courage and Hermione's intelligence combined, and they face new magical threats together as a family, protecting the wizarding world in a new era.