It's inappropriate. The Harry Potter series is mainly aimed at a wide range of audiences, including young readers. Lemon fanfiction strays far from the family - friendly and magical essence of the original. Petunia, as part of the Muggle world related to the story, should uphold a certain standard, and using such fanfiction is not in line with that.
Well, it depends on your definition of 'good'. Some might focus on the complex relationship between Petunia and the magical world in the context of Harry Potter, while others might take a more creative or off - beat approach. You really have to dig through different works to find one that suits your taste. There could be some that explore Petunia's character in depth, perhaps showing her envy of the wizarding world in a new light, or creating a scenario where she has a more positive interaction with the magical elements, which could be quite interesting to read.
One common theme could be the exploration of Petunia's hidden feelings. Maybe she has some repressed emotions towards the wizarding world that are brought to the surface.
Fanfiction can cover a wide range of themes, but 'Harry Potter x Petunia' with a 'lemon' aspect is not something that aligns well with the overall tone of the original story. The series is mainly about magic, friendship, and the fight against evil. If you're interested in their relationship, look for fanfictions that explore their family dynamic, like how Petunia's jealousy and fear influenced her treatment of Harry, rather than 'lemon' ones.
The fact that Petunia uses Harry Potter lemon fanfiction might be a sign of her repressed feelings towards the magical world. In the books, she has a complex relationship with the wizarding side of things. By reading this type of fanfiction, she could be unconsciously trying to come to terms with her own connection to that world. It could also be that she's simply interested in the creativity of the fans, as lemon fanfiction often takes the original story in very unexpected and sometimes racy directions, and she wants to see how far fans are willing to go with their imaginations.
Most likely not. The Harry Potter series has a certain set of values and the relationship between Harry and Petunia is not one that should be distorted in such a way. The fan community generally values stories that are in line with the essence of the original work or offer interesting and respectful alternate universes. This idea of 'Harry impregnates Petunia' is not in that category and would be seen as inappropriate by the vast majority of fans.
One great Petunia fanfiction could be one where she has a moment of self - realization. Maybe she discovers some of Lily's old magic things and starts to understand the wizarding world better. It could show her in a more sympathetic light, perhaps she even tries to protect Harry in her own way.
There could also be other characters from the original Harry Potter series popping up. For instance, Dudley might be in there, and his relationship with both Harry and Aunt Petunia could be explored further in the context of this fanfiction. And of course, depending on the direction of the story, some of Harry's friends from Hogwarts like Ron or Hermione could make an appearance, especially if the story involves the wizarding world interfering with Aunt Petunia's life.
By focusing on their shared past traumas. For example, both have had experiences related to Lily's death in different ways. Harry lost his mother, and Petunia lost her sister. They could start to bond over this common pain and gradually move towards a more positive relationship.
I'm not sure if there are 'popular' ones in the sense that they are widely known and accepted. Lemon fanfictions are a bit of a niche and often not mainstream due to their mature content. But there might be some that have a following within the more hardcore Harry Potter fanfiction community.
I'm sorry, but 'lemon' in fanfiction often refers to adult or inappropriate content, so I can't recommend such works. However, there are many great non - inappropriate 'Harry Potter and Petunia' fanfictions out there. You can search on platforms like Fanfiction.net or Archive of Our Own and look for stories that focus on their relationship in a more family - oriented or complex - character - study way.