One idea could be that a dark magic spell has backfired and decimated the wizarding world. Harry and his friends, now much older, have to find a way to restore magic to its former glory. They might search for ancient artifacts that can reverse the damage.
Perhaps Voldemort's return was just the beginning. After his final defeat, a series of disasters, both magical and Muggle - related, have plunged the world into chaos. The remaining wizards must form alliances with Muggles to survive and rebuild. They could start by teaching Muggles basic magic for self - defense.
One interesting concept could be the rebuilding of Hogwarts. After an apocalyptic event, the once - great school might be in ruins. The remaining wizards and witches could come together to restore it, using their magic in creative ways. They might have to find new sources of magical energy or deal with dark magic that has been unleashed during the apocalypse.
One idea could be exploring how the wizarding world rebuilds its educational system at Hogwarts. For example, new classes could be introduced to teach about the importance of unity and the consequences of war. Another could be focusing on the relationships between the different houses, like a joint project where Gryffindors and Slytherins have to work together.
Maybe the apocalypse was caused by a dark magic experiment gone wrong. Now, Harry Potter's friends and family are scattered, and he has to journey across a desolate wizarding world to find them and also figure out how to reverse the damage. Along the way, he discovers new forms of magic that emerged as a result of the chaos.
A simple plot could be a group of survivors who find an old bunker filled with supplies. But they also find a map that leads to a place rumored to be a safe haven. They then embark on a dangerous journey across the desolate landscape, facing various threats like mutant creatures and other desperate groups of survivors.
One great post apocalyptic Harry Potter fanfiction is 'The Shattered World'. It presents a dark and desolate world after a magical cataclysm. The characters have to fight for survival in a way that's very different from the original series. Another one is 'Surviving the Ruins' which focuses on how the Hogwarts students band together against new and terrifying threats.
In post apocalyptic Harry Potter fanfiction, a common theme is the breakdown of the old order. Hogwarts might no longer be the safe haven it once was, and the Ministry of Magic could be in ruins. This forces the characters to create new systems and ways of living. Another theme is the discovery of new powers or abilities. With the world in chaos, some characters may find hidden strengths within themselves that they never knew existed before, which helps them in their fight for survival.
One idea could be about Harry starting his own school of magic. He could combine the best of Hogwarts with new and innovative ways of teaching magic, like including Muggle technology in some lessons. Another idea is a fanfic focusing on Hermione's work in the Ministry of Magic, perhaps she's in charge of reforming some archaic laws regarding house - elves. A third idea might be a story about Ron and Neville opening a magical joke shop together, filled with all kinds of hilarious and magical prank items.
A great plot for a Potter Manor fanfiction could involve a mystery that surrounds the manor. For instance, strange noises at night lead Harry to uncover a long - forgotten chamber. It could also be about Harry restoring the manor to its former glory, perhaps with the help of Hermione's research on ancient magic used in the construction of such manors.
A traveler could be from a different magical realm entirely and come to the Harry Potter universe. They bring with them unique magical abilities that both fascinate and frighten the wizards in the Harry Potter world. This could lead to a series of adventures where they either share their knowledge or are hunted down by those who fear the new magic they possess.
One idea could be that Hecate, being the goddess of magic, takes Harry Potter under her wing secretly to teach him ancient and powerful magic that Dumbledore doesn't know. This could lead to Harry having new abilities to fight Voldemort.