Yes, there are likely fanfics out there with the concept of Harry Potter being a baker. The 'Harry Potter' fandom is vast, and fans often come up with creative and unique scenarios for their fanfictions. Some might be interested in exploring what Harry would be like in a more mundane job like baking, away from the wizarding world's battles and magic.
In a 'Harry Potter is a Baker' fanfic, Harry might be using his magic to add a special touch to his baking. For example, he could use a spell to make his dough rise instantly or his cakes have a unique, magical flavor. He could also meet other magical beings in his bakery, like house - elves who help him out in the kitchen. And perhaps he uses his fame as 'The Boy Who Lived' to attract customers, but also has to deal with some who are just there for the novelty and not the actual baked goods.
One plotline could be Harry starting his bakery in Diagon Alley. He might face some initial resistance from the more traditional wizarding families because of his sexual orientation, but gradually wins them over with his delicious magical baked goods. Another could be that he uses his baking skills to raise funds for a magical LGBT+ organization in the wizarding world.
In Harry Potter fanfic, the idea of a 'creature baker' is quite unique. It might not be a common trope, but perhaps in some more niche fanfics, there could be a character who bakes things inspired by magical creatures. For example, they could make cakes that look like hippogriffs or cupcakes shaped like house - elves. But it would take some digging to find such specific fanfics.
A 'creature baker' could be a source of unique magical treats. For example, they could make biscuits that give the eater the ability to communicate with certain magical creatures for a short time.
One possible plot could be that Harry, after the war, decides to pursue baking as a form of therapy. He starts a small bakery in Hogsmeade and uses his magic to create unique baked goods. His friends come to support him, and he ends up using his baking to bring the wizarding community closer together.
There may be such a fanfiction. You could also try joining Harry Potter fan groups on social media platforms and asking for recommendations. People in those groups are often very enthusiastic about sharing their favorite fanfictions. In a 'Harry Potter is a Baker' fanfiction, perhaps Harry uses his knowledge of potions to create new and exciting flavors for his baked goods, adding a whole new layer of creativity to the story.
I'm not sure specifically if there is a fanfic with that exact title. However, in the world of fanfiction, there are countless creative and diverse interpretations of Harry Potter characters. A 'gay baker' concept for Harry Potter could be an interesting exploration of his character in a different life scenario, perhaps exploring themes of acceptance and a newfound passion for baking in a wizarding world context.
Well, just based on that title alone, it's difficult to determine its quality. There are so many aspects that make a Harry Potter fanfic great. For example, it could explore new relationships between the characters, or create exciting new magical adventures. But we don't know if 'skull is harry potter fanfic' does any of those things. So, it might be good, it might not.
I'm not sure if it's common. There are so many different types of fanfics in the Harry Potter fandom. Some focus on relationships, others on new adventures. While metamorph - related ideas are interesting, it might not be as common as, say, romance - centered fanfics.