In the 'Harry Potter opens a pet shop' fanfiction, he would surely attract all kinds of customers. Witches and wizards from Hogwarts and other places would come. He could have special sections for different types of pets. For example, a dark corner for nocturnal magical creatures. And he might have to deal with some mischievous pets causing chaos in the shop from time to time.
Well, he might sell magical creatures like owls, toads, and perhaps even some rare and exotic ones like hippogriffs. He could use his knowledge of magic to take care of the pets and also teach the customers how to handle them properly.
Well, he might create some unique potions. Maybe a potion that can make people temporarily have the ability to speak Parseltongue. It would attract a lot of curious wizards and witches to his shop.
It could be Hagrid. He loves all kinds of magical creatures and would be very interested in seeing what Harry has in his pet shop. He might even give Harry some advice on taking care of the more dangerous ones.
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, he might open a magic shop. He could sell all kinds of magical items like self - writing quills, enchanted maps, and potions. Maybe his friends would help him run it. For example, Hermione could manage the accounts and Ron could test the products.
Other potion shop owners might visit too. Not as customers in the traditional sense, but more to check out the competition. They might be curious about Harry's unique potions. And then there are the local wizards and witches in the area where the shop is located. They could need potions for daily life, like a potion to make their gardens grow better or a potion to keep their pets healthy.
One possible plot could be that a new, mysterious pet appears in the pet shop in Diagon Alley. This pet has some unique magical abilities that no one has ever seen before. A young witch or wizard discovers it and tries to figure out its origin and how to take care of it. Maybe it's a key to an ancient magic mystery.
Perhaps the hellhound has a special power like being able to travel through fire unharmed. This power could play a crucial role in the story. For example, the main character and their friends get trapped in a burning building, and the hellhound uses its power to create a path through the fire, allowing them to escape. The fanfiction could then focus on how they keep this power a secret from the school authorities.
One main character could be a young, aspiring wizard who has always dreamed of having a magical pet. He visits the pet shop regularly to look at all the amazing creatures. Another could be the eccentric old owner of the pet shop who has a wealth of knowledge about magical pets.
Well, in fanfiction, Harry Potter visiting a travel shop could lead to all sorts of adventures. He could meet some interesting characters there, like a seer who gives him a cryptic message about his next journey. The travel shop could be filled with enchanted maps and magical travel devices. He could be tempted by a special broomstick that can fly long distances without getting tired, which would be very useful for his travels.
Harry Potter himself could be a main character. He might be on a mission to find a pet for a friend or to solve a mystery related to the pet shop. Hermione would also be a great choice as she's always interested in learning about new magical creatures. And Hagrid, of course, with his love for all beasts, could play a major role.