Yes, there are some. For example, 'A Different Path' is quite popular. It explores an interesting relationship between Percy and Lupa in a unique setting. The author does a great job of developing their characters and the story has some exciting plot twists.
Another theme is transformation. In many fanfics, Percy's relationship with Lupa causes him to transform, not just in terms of his powers but also his understanding of loyalty and leadership. Lupa represents a different kind of power and wisdom, and Percy has to adapt to that. For example, in some stories, he becomes more in tune with his animal instincts because of her influence. This transformation theme adds depth to their relationship.
There's a fanfic called 'Aphrodite's Affection for Percy'. In this one, Aphrodite takes a special interest in Percy for reasons other than her usual matchmaking. It shows a more complex side of her character and how Percy reacts to her attention. It's a good read if you like exploring different relationships within the Percy Jackson universe.
In this fanfiction, there might be a lot of focus on Percy's relationship with the other wolves in Lupa's pack. He could learn their ways of survival, their hierarchy, and how to be a part of their community. This would be a great way to explore his adaptability and growth.
Lupa herself would be a major character. She's the one who has a special connection to Percy in this story. She could be guiding him, testing him, or having her own motives that are intertwined with Percy's journey.
The setting of the story might shift a bit. Instead of always being at Camp Half - Blood or on quests related to the Greek gods, Percy could be in the territory of the wolves. There could be new threats and challenges there, like rival wolf packs or ancient enemies of Lupa. And all these elements would make for an exciting and different take on the Percy Jackson universe.
In Percy Jackson fanfics, Percy is often depicted as a brave and resourceful hero. Lupa, the wolf goddess, might be shown as a strict but fair mentor. As for the 'lemon' aspect, if it's a reference to the citrus fruit, it could be used in a symbolic way, perhaps representing freshness or something unique in the story. For example, it could be part of a potion or a special item in the fanfic world.
A prevalent theme is isolation. In many fanfictions, Percy feels alone because of his strange heritage. He doesn't quite fit in with the normal demigods. Also, the theme of destiny often comes up. He has a special destiny due to his parents that he is constantly striving to fulfill.
I've read a fanfiction where Percy is the son of Lupa and Chaos and it focuses on his relationships. 'Percy's Bonds' is the name. It shows how his different heritage affects his friendships and romances, and how he has to come to terms with who he really is in the context of his relationships.
One common theme is identity. Since Percy has two very different divine parents, he often struggles to figure out who he really is in fanfictions. Another theme is power. With the combined powers of Lupa and Poseidon, his power levels and how he uses them are often explored. Also, acceptance by his peers is a big theme as they may view his dual heritage as strange or overpowering.
One interesting plot could be Percy having to prove himself to Lupa's pack in a series of dangerous trials. Maybe he has to hunt a mythical beast that has been terrorizing the pack's territory.