Is there any good 'Percy Jackson Son of Gaea and Poseidon' fanfiction?

Yes, there are quite a few. You can start by looking on fanfiction websites like Archive of Our Own or FanFiction.net. Some might explore Percy's unique heritage as the son of both Gaea and Poseidon and how it affects his relationships with other characters in the Percy Jackson universe, like his friends at Camp Half - Blood or his enemies.

There is. I've read some where the author delved into the internal conflict Percy would face. Being the son of Gaea, who is often seen as a villain in the series, and Poseidon, a major god. It creates an interesting dynamic as Percy tries to reconcile these two very different heritages. He might struggle with his identity and question his loyalties, which makes for a really engaging read.

Definitely. A lot of fanfiction in this area might take Percy on different adventures that are influenced by his dual parentage. For example, he could have powers that are a combination of Gaea's earth - related abilities and Poseidon's control over water. Some fanfictions might show him using these powers in new and creative ways to fight against new threats in the world of the story, or even to resolve old conflicts in a different light.