Well, it's not as popular as some other pairings in the Percy Jackson fandom. Gaea is a major antagonist in the series, and the idea of her in a romantic relationship with Percy is rather unorthodox. So, compared to more common pairings like Percy and Annabeth, it has a much smaller following.
In the Percy Jackson series, Gaea is a villain, and a love relationship between Percy and her in the context of the original story is very unlikely. However, in the world of fanfiction, anything can be created. There might be some fanfictions exploring such a strange and dark concept, but it would be a very unorthodox take on the characters.
Some dedicated Percy Jackson fan communities might also be a good place to look for such fanfiction. These communities often have members who share their own works or know where to find specific types of fanfictions. You could join forums or groups related to Percy Jackson and ask around there.
If there were a Percy Jackson - Gaea love fanfiction, it could be a very complex story. Gaea, as the primordial being representing the earth, might have a different view of Percy. She could see him as a powerful force in his own right and be attracted to that. Percy, on the other hand, might be conflicted. He's supposed to fight against her, but this newfound connection makes him question everything. The fanfiction could explore how they navigate this relationship in a world where their love is seen as taboo.
One great 'Percy Jackson Gaea' fanfiction is 'The Battle Against Gaea's Wrath'. It continues the story after the end of the main series, with Percy and his friends facing new threats related to Gaea. The author does an amazing job of keeping the characters' personalities intact.
One possible fanfiction could be about Percy Jackson having a strange encounter with Gaea's power while in a lemon grove. Maybe the lemon trees are enchanted by Gaea, and Percy has to figure out how to break the spell without getting caught in Gaea's grander plans for chaos.
In some fanfictions, Gaea's love for Percy could be a curse placed on her by some other deity. Percy initially is repulsed but as the story progresses, he realizes that there's more to Gaea than just the evil being he knew. The fanfic could then delve into how they both try to break the curse and in the process, understand each other better. It could also involve other characters from the Percy Jackson series reacting to this strange relationship.
In a fanfic, Percy could have a mental battle with Gaea where the lemon plays a key role. Imagine Percy enters Gaea's mind - realm. There, he finds a withered lemon tree. By using his willpower and connection to the ocean (as water is also related to life like the lemon), he tries to revive the tree. As he does this, Gaea is forced to watch and is affected by his actions. If he succeeds in making the tree bloom again, it could signify his victory over Gaea's destructive plans.
A common theme is redemption. Many fanfictions explore the idea of Gaea being redeemed through her interaction with Percy. Since Percy is often seen as a symbol of hope and goodness in the original series, his influence on Gaea can be a way to show that even the most malevolent beings can change.
Well, it could be a really wild ride. Percy joining Gaea would be such a shock to his friends. They would probably think he's been brainwashed. And Percy himself might be in for a rude awakening when he sees Gaea's true intentions. She could be using him to get to other demigods, or to start a war between the gods and the demigods. He'd have to figure out a way to break free from her influence before it's too late.