The goddess could also be an original creation for the fanfiction. A being with a unique set of powers like the ability to control time and space. This goddess could be betrothed to Harry to stop an impending doom that threatens both the wizarding and Muggle worlds. Her powers would be so great that she needs Harry's connection to the wizarding world to fully utilize them and save the day.
Well, it could be that Harry discovers his betrothal to a goddess through some magical means. Maybe a prophecy or an ancient magic. The goddess could be from a different magical realm and bring all sorts of new magic and challenges into Harry's life. Their relationship might start rocky as Harry is used to the Muggle - born and wizarding world rules, but gradually they learn to understand and love each other.
There probably is. Fanfiction writers like to explore different pairings and scenarios in the Harry Potter universe. Given the popularity of the series and the diverse creativity of the fan base, it's not surprising that someone might write a story where Harry Potter is betrothed to someone from the Black family. You could also check out some Harry Potter fanfiction forums where people might recommend such stories.
Perhaps the Black family member is in danger, and the betrothal is a way to protect her. Harry gets involved in the Black family's secrets and power struggles while trying to uphold the betrothal. Another plot could be that it was a magical accident or a prophecy that led to the betrothal, and they have to figure out how to deal with it.
There is definitely some. One thing to keep in mind is that the quality can vary a great deal. Some fanfictions might take a more romantic approach, showing Harry and Cho's betrothal as a chance for them to really understand each other on a deeper level. Others might add in elements of mystery or adventure, like dealing with dark wizards who oppose their union. It really depends on what you're looking for in a fanfiction.
It could be Athena. Athena is known for her wisdom in Greek mythology. She could pass on her wisdom to Harry, making him not just a powerful wizard but also a very wise one. He could use this wisdom to solve problems in the wizarding world in a more strategic way.
The goddess could be an ancient Celtic deity. In the fanfiction, the author might choose a Celtic goddess because of the rich magical lore associated with them. For example, Morgan le Fay from Arthurian legend could be reimagined as a goddess in this context, and she could adopt Harry due to her interest in powerful magic users.
She could be an ancient Celtic goddess, like Brigid. Brigid is associated with magic, healing, and smithcraft in Celtic mythology. In the fanfiction, she might see Harry's potential and decide to train him in her unique magical arts.
One possible goddess could be Athena. In the context of the fanfiction, she could bring her wisdom and strategic skills to help Harry Potter. Another could be Aphrodite, adding an element of love and charm to the story, perhaps using her powers to influence the emotions of characters for good or bad depending on the plot.