A potential love interest. Since it's a gay club, he might meet someone who catches his eye romantically. This person could be from a different background, with different values and interests, which would make for an interesting relationship dynamic in the fanfiction.
A mentor - like figure. There could be an older, wiser person at the club who has been through a lot in the LGBT+ community. This person could offer Harry advice on how to navigate his new experiences, whether it's about coming to terms with his own identity or dealing with any potential discrimination in his fictional world.
He could meet other fans of the same fictional universe. In some fanfictions, gay clubs are places where fans gather to discuss their favorite characters and storylines. So Harry might run into people who are also fans of his world.
He might meet his parents. Since they have passed away, the other side of the veil could be a place where they exist in some form.
There's a chance he'll meet other outcast wizards. These wizards might have been shunned by the wizarding world above ground. They could be very different from the wizards Harry is familiar with, perhaps having their own unique styles of magic. They might initially be hostile to Harry, seeing him as an outsider from the 'normal' wizarding world, but later they could become his allies. They might also know secrets about the underground world that could help Harry in his future battles or quests.
He could meet a young and brilliant wizard inventor. This inventor is working on some newfangled magical gadgets and shows Harry some prototypes, like a self - flying broomstick that can change its shape according to the rider's mood.
In the fanfiction, Harry could meet Native American wizards or witches who have a deep connection to the land and ancient magic. Their magic might be based on nature and spirits in a way that is very different from what Harry is used to in Britain. He may also meet some Muggle - born American wizards who have a different perspective on being part of the wizarding world, having grown up in a different cultural and social environment compared to Harry.
There's a chance he'll run into Ron. Maybe Ron is looking for some new wizarding sweets at Honeydukes, and they end up sharing some of the treats while they continue their shopping spree. And it's possible that they'll see Neville there too, who is searching for some rare plant seeds for his Herbology studies.
In this fanfiction, Harry might meet students from various backgrounds. There could be students from far - off magical lands who have their own unique cultures and magic. He could also run into some Beubaxtons alumni who come back to visit and they might share some interesting stories or give him some advice on how to make the most of his time at Beubaxtons.
He could meet his future self. This would be a very interesting encounter as he could learn from his future self about what he has accomplished and what mistakes he should avoid. He might also meet the future generations of his family, like his grandchildren or great - grandchildren.
Perhaps Harry will run into an old wizard who has been in the hospital for a long time. This wizard has a lot of stories about the old days of the wizarding world and gives Harry some valuable advice.
He could also meet some minor nymphs or spirits that inhabit the island. These beings might be curious about Percy's return and have their own stories to tell. For instance, there could be a water nymph who has some knowledge about a prophecy related to Percy and his return to Ogygia. Or a spirit that has been observing the changes in Ogygia since Percy last left and can give him some insights on what has been going on in his absence.
In some fanfictions, Harry might meet a goblin with a special mission for him. This goblin could be an outcast among his kind and believes that Harry is the only one who can help. So, he takes Harry on a journey through the deepest parts of Gringotts, where Harry gets to see parts of the bank that no one else has ever seen. During this journey, Harry also meets other strange and interesting characters that are somehow connected to the goblin's mission.