It could be that Harry discovers a new kind of magic within the context of his priesthood. He might be in a world where the line between magic and religious miracles is blurred. He could be on a quest to understand this new form of power, all while performing his duties as a priest, which would include counseling parishioners, performing religious ceremonies, and dealing with the politics of the church.
Perhaps Harry becomes a priest to atone for the sins and destruction caused during his battles in the wizarding world. His journey could involve him trying to bring peace and spiritual guidance to a war - torn or troubled community. And along the way, he might face challenges from those who sense his 'different' past.
One possible plotline could be Harry being easily tricked by dark wizards who take advantage of his naivete. For example, they might convince him to perform dangerous spells or go to forbidden places. Another could be that he misinterprets the intentions of his friends, causing some rifts in their relationships until he eventually learns the truth. Maybe he also gets involved with some new magical creatures that he wrongly believes are harmless because of his naivete.
One possible plotline could be Harry using his vegan lifestyle to promote animal rights in the wizarding world. He might start a club or campaign within Hogwarts to encourage others to be more conscious about their food choices.
One possible plotline could be that it's the result of some dark magic gone wrong. Maybe a spell was cast on Harry by an enemy of Snape's to embarrass him, and now they have to deal with the consequences together. Another could be that it's part of a prophecy that no one expected, and they must figure out how it fits into the wizarding world's future.
One possible plotline could be Harry trying to gain Tywin's approval while also holding onto his own values. Another could be Harry using his unique skills to help Tywin in his political maneuvers.
One possible plotline could be that Harry, through some magical accident or inheritance, comes to own Draco's family manor. Draco is then forced to interact with Harry on Harry's terms to regain his family's pride. Another could be that Harry wins a bet against Draco and the terms of the bet are such that Harry now has ownership over Draco's time, making Draco do tasks for Harry.
One possible plotline could be Harry being sold due to some dark magic plot against him. Snape then has to deal with this unexpected situation and protect Harry from further harm. Another could be that it's a part of a deal to save the wizarding world, and Snape and Harry must learn to work together in this strange new dynamic.
One plotline could be that fem Harry discovers a hidden connection to Morgana through her magic. Maybe she has some latent powers that are related to Morgana's, and she has to explore this connection to understand more about herself and her place in the magical world.
Perhaps Harry discovers that he has basilisk blood in him. This could change his abilities and how others view him. He might face discrimination from some in the wizarding world who fear the basilisk's power, while others might see him as a potential weapon against Voldemort. The plot could revolve around Harry coming to terms with this new aspect of himself.
One possible plotline could be that Harry, as a cyborg, uses his mechanical abilities to enhance his magic. For example, he might have a built - in spell - enhancer in his robotic parts that allows him to cast more powerful spells. Another could be that he has to hide his cyborg nature from the wizarding world at first, fearing they will reject him, but then uses it to fight a new kind of dark force that is immune to normal magic.
One possible plotline could be that the wizarding world has its own version of cops. Harry Potter and his friends could join this force and use their magic to solve magical crimes that the regular Aurors can't handle. For example, they might deal with dark wizards who are using new and undetectable forms of dark magic.