Perhaps the plot revolves around a situation where Hogwarts is in a different kind of danger. Not just from Voldemort - like threats, but something more internal. For example, a curse that is slowly destroying the school, and Harry is the only one who can sense it. He then has to go on a quest to find the origin of the curse and a way to stop it, all while dealing with the disbelief of some of his friends and teachers. It would really put him in the position of a hero in a unique way.
It could be about Harry facing a new, extremely powerful dark wizard that no one else seems to be able to handle. So, he has to step up even more than he did in the original series and become a true hero. Maybe he has to find a new kind of magic or form an unlikely alliance to defeat this new threat.
One great place to find 'In Need of a Hero' Harry Potter fanfiction is on Fanfiction.net. It has a vast collection of fan - created stories. You can simply search for the title or relevant keywords like 'Harry Potter' and 'In Need of a Hero' in the search bar, and it'll show you a list of available fics. Another option is Archive of Our Own (AO3). It also has a great tagging system which can help you narrow down your search to find the exact fanfiction you're looking for.
One possible plot could be that a beloved hero character, perhaps someone inspired by the original Harry Potter series, sacrifices themselves to save the wizarding world from a new and powerful dark force. This selfless act would be in line with the themes of heroism in the original series.
One possible plot could be that a wizard has the ability to 'rent a hero' from a magical service. Harry Potter himself could be rented out to help a young, struggling wizard face a new dark threat in the wizarding world. He could use his skills and experiences to train this wizard and together they could uncover a plot by a group of Death Eaters who are trying to revive Voldemort in a new way.
The plot could involve a situation where a new form of dark magic is unleashed in the wizarding world, which spreads like wildfire and causes destruction similar to 911. The Ministry of Magic is caught off - guard. Hermione, with her vast knowledge, starts researching a way to counter this magic. Meanwhile, Ron and Harry lead the effort to protect the civilians. They set up shelters in places like the Room of Requirement and use Patronuses to guide people to safety. As they dig deeper, they discover that this dark magic was a planned attack by a long - hidden dark wizard group who wants to take over the wizarding world.
Ron Weasley could also be the partially kissed hero. In some fanfictions, Ron might have a moment with a girl where they start to kiss but are interrupted. He's a character who has his own share of romantic interests in the series, and this could be an interesting take on his character in fanfiction.
Maybe Harry could be the host of the Kyuubi's power in the wizarding world. He would have to deal with not only the threats from Voldemort but also the power of the Kyuubi inside him. His friends might be both amazed and a bit scared of this new power source.
Well, it could be about Harry Potter somehow taking on the characteristics or abilities of Alastor Moody. Maybe he has to pretend to be Moody for a mission and in the process, he learns a lot about Moody's past and his way of dealing with dark wizards.
One possible plot could be that Harry, after the war, decides to pursue baking as a form of therapy. He starts a small bakery in Hogsmeade and uses his magic to create unique baked goods. His friends come to support him, and he ends up using his baking to bring the wizarding community closer together.
One possible plot could be that Sauron somehow manages to enter the wizarding world. Maybe through a powerful dark magic spell that links the two universes. Harry, being the hero, senses the new and greater evil. He then has to figure out how to defeat Sauron, which is much more difficult than any foe he has faced before. He might have to learn about the power of the One Ring and how to destroy it, all while protecting Hogwarts and the wizarding world from Sauron's dark minions.
The plot might involve a crossover where the magical world of Harry Potter collides with the concept of balverines. Maybe Harry and his friends encounter balverines during one of their adventures outside of Hogwarts, and they have to use both their magic skills and newfound knowledge about balverines to survive.