There could be. Fanfic communities are quite large and diverse. But it might be a bit hard to find exactly that specific combination of 'Harry Fleur pregnant harem'. You may need to use specific search terms and filters on relevant platforms. Some fanfic writers like to explore unique and interesting concepts like this.
One common theme could be relationship dynamics. With Fleur being pregnant and in a harem - like situation, there would be a lot of complex relationships to explore, such as how Harry interacts with Fleur and the other members of the harem. Another theme might be the challenges of a non - traditional family structure that comes with the harem concept and the pregnancy.
Often, Luna Lovegood can be found in such fanfictions. Her unique and dreamy nature could bring a different dynamic to the harem. Neville Longbottom might also be involved in some way, perhaps as a friend who supports the harem and helps them out in times of need. There could also be some foreign exchange students or magical creatures in human form that end up in the harem for various reasons.
Harry would likely become more responsible and mature. The news of Fleur being pregnant would force him out of his comfort zone and make him think about the future in a more serious way. Fleur would also change, she might become more protective and nurturing. Her Veela side might also come out more in terms of being possessive of Harry and the unborn child.
In a 'harry gets fleur pregnant fanfic', perhaps the plot could involve Harry and Fleur having to hide the pregnancy at first. Maybe Voldemort is still a threat or there are other dark forces at play. As Fleur's pregnancy progresses, they might discover that the child has some unique magical abilities that could either be a great asset or a dangerous liability. Harry would then be in a race against time to ensure the safety of his family while also dealing with his own internal turmoil about becoming a father so suddenly.
In many fanfics, Fleur is often depicted as strong - willed. She's a Veela, so she has that alluring quality, but she's also smart and not just a pretty face. For example, in some fanfics she uses her Veela charm in a strategic way to get what she wants or to protect others.
There could be a fanfic where Fleur is given a lemon as a symbol of good luck before a big event in the wizarding world. And she has to figure out how to use the magic within the lemon to her advantage. It could be a simple yet interesting concept where the lemon holds a special kind of magic that only Fleur can unlock because of her connection to different magical cultures.
Well, a common plotline is the development of relationships within the harem. For example, Harry might initially be a bit hesitant about the whole harem concept, but as he gets to know Fleur and the other potential members, he starts to embrace it. There could also be a plot where they are all on a quest to discover some ancient magic, and during this journey, their bonds in the harem become deeper and more complex.
There is 'The Unexpected Love'. In this fanfic, Fleur's pregnancy brings out a protective side in Harry. It has a lot of heartwarming moments as they navigate their new relationship and the upcoming addition to their world. The author does a great job of portraying their emotions.
Perhaps in the fanfiction, there is some sort of magic gone wrong. Harry and Fleur are caught in a magical spell that makes them act out of character. This leads to their relationship becoming more intimate than expected and Fleur getting pregnant. The rest of the story might be about them trying to reverse the spell while also coming to terms with the pregnancy.