Perhaps a story could focus on the exploration of new magic. In the 20 years, some wizards might have delved deeper into forgotten or prohibited magic. This could lead to a conflict between those who want to preserve the old ways and those who see the new magic as a way to progress. Harry and his comrades might have to decide which side to take or find a middle ground.
One possible storyline could be the children of the original characters starting their own adventures at Hogwarts. They might face new threats that are related to the past but in a different way. For example, a new dark wizard could be trying to revive the ideas of Voldemort and the kids have to stop it using the knowledge passed down from their parents.
Maybe some of the old grudges between wizarding families that were thought to be resolved start to flare up again. This could lead to a lot of political intrigue within the wizarding community. And the children of the main characters could get caught up in this web of family feuds, having to decide whether to follow their family's old ways or try to make peace.
One possible storyline could be that the Dursleys' pet, perhaps their cat, discovers Harry's wizarding abilities before the Dursleys do. It might then have some comical or tense interactions with Harry, like trying to stop him from using magic in the house for fear of getting in trouble itself.
One possible storyline could be that Harry is on the run from dark forces again and the tent serves as his only safe haven. He might be using magic to conceal the tent and make it a cozy, self - sufficient living space, with magical wards all around it for protection.
Perhaps in the fanfiction, Harry discovers that his grandparents had a hidden magical legacy. They had been working on a powerful charm to protect the Potter family long before Harry was born. Harry finds clues about this charm and with the help of his friends, he tries to complete it, believing it could be the key to finally defeating Voldemort.
In some fanfictions, Harry might become a very influential Auror, traveling around the wizarding world to fight dark magic remnants. He could also be involved in reforming the Ministry of Magic, ensuring fairness and equality for all magical beings.
Another storyline could be that Harry goes to Bulgaria to hide from the threats in the UK wizarding world. While there, he has to adapt to a new culture and way of life. He could start teaching at a Bulgarian wizarding school, sharing his knowledge of Defense Against the Dark Arts. He might also fall in love with a Bulgarian witch and have to deal with the cultural differences in relationships.
One possible storyline could be that Steven Stone, with his knowledge of stones and gems, discovers some magical gems in the Harry Potter universe. These gems could have unique magical properties that are unknown to the wizards. He teams up with Harry Potter to protect these gems from dark wizards who want to use them for evil. For example, the gems might be able to enhance spells or open portals to other magical dimensions.
In this fanfiction, it could be that Hogwarts has been shut down due to some great danger. Harry Potter then decides to gather a group of like - minded young wizards and witches. They form their own makeshift magical school in a hidden location. They have to learn magic without the guidance of Hogwarts' professors, so they rely on old magic books and their own wits to develop their magical abilities and face the threats that led to Hogwarts' closure.
Perhaps the story could involve Harry's child having special powers or a prophecy attached to them. Harry, as a single father, would then be extra protective and determined to keep his child safe from those who might want to use their power for evil. He'd have to rely on his friends, like Hermione and Ron, for support in both parenting and protecting the child.
It could be about Harry, Ron and Hermione's careers. Maybe Harry is now a high - ranking Auror, leading teams to fight the remaining dark wizards. Ron could be running Weasley's Wizard Wheezes successfully, and Hermione might be making great changes in the Ministry of Magic with her intelligence.