Well, he could open a magical creature adoption center. He'd use his knowledge of Hogwarts' grounds and the Forbidden Forest to rescue and rehabilitate magical creatures. Then he'd find suitable homes for them among wizarding families. It would be a great way for him to give back to the magical community and also educate people about proper care of these unique beings.
Hermione would be a great partner. Her intelligence and knowledge of magic would be invaluable. For example, if Harry opened a potion - making business, Hermione could handle the research and development of new potions, while Harry dealt with the business side like marketing and customer relations.
Fanfiction can increase the overall popularity of the 'Harry Potter' world, which in turn benefits the business. More people talking about fan - made stories can draw in new fans to the official franchise, leading to more sales of books, movies, etc.
Well, he might use magic to create the most amazing pastries. His Firebolt skills could translate to lightning - fast kneading of dough. And his Hogwarts friends would surely visit often, like Hermione might help with the bookkeeping using her intelligence and Ron would be there to taste - test everything.
Well, it could be a magic item store. He might sell things like rare wands, enchanted potions, and magical maps. After all, he has a lot of experience with these things from his adventures at Hogwarts.
Well, perhaps the plot could involve Harry using his fame and fortune to open an orphanage. He might use his magic to create a safe and magical environment for the orphans. Maybe he'd teach them magic himself, or bring in some of his Hogwarts friends as teachers. It could also show how he deals with the challenges of running an orphanage, like getting enough funds and handling difficult children.
Well, he might serve magical drinks like Butterbeer-flavored coffee. His cafe could be a place where wizards and muggles alike gather. He could use magic to decorate the place with floating candles and moving portraits. Maybe his friends from Hogwarts would help out, like Hermione managing the accounts with her intelligence and Ron being in charge of the food tasting.
One possible plot could be that Harry uses his magical knowledge to create a bar with unique magical drinks. For example, he might serve Butterbeer with an extra kick of magic, or a potion - like cocktail that gives temporary magical abilities. He could also use the bar as a place for magical creatures and wizards to mingle, creating a new social hub in the wizarding world.
Well, perhaps Harry uses magic to create the most amazing and unique pastries. He could make cakes that levitate a bit when you cut into them. And his potions knowledge might come in handy for creating special flavor combinations that Muggles have never tasted before.