Yes, there are quite a few. You can start by looking on popular fanfiction websites like FanFiction.net or Archive of Our Own. Just search for 'Ash loves Gary' and you'll likely find a variety of stories with different plotlines and writing styles.
The popularity might stem from the fact that Ash and Gary have a long - standing rivalry in the original Pokemon series. Changing that into a love story is a big departure from the norm and thus intrigues many fans. It allows for a lot of character development and exploration of emotions that were not really present in the original series.
The main characters are obviously Gary and Ash. Gary is often depicted as having a complex personality, being competitive yet also having this newfound love for Ash. Ash, on the other hand, is usually his usual self - kind, determined, and focused on becoming a pokemon master.
Another option is Wattpad. While it has a wide range of content, it also has some Pokémon fanfictions. You can search specifically for 'Ash loves Gary' and see what pops up. However, be aware that the quality and content may not be as regulated as on some other platforms, so you might need to do a bit more sifting through the results.
One popular 'pokemon ash loves gary fanfiction' might be the one where Ash realizes his feelings during a tough pokemon battle against a powerful opponent. In that story, the shared experiences of their pokemon journeys and the intense emotions of the battle make Ash see Gary in a new light.
There could be a story where Gary realizes his love for Ash during a journey. They might be separated for a while, and during that time, Gary comes to terms with his feelings. When they reunite, he has to figure out how to express his love without ruining their friendship, which makes for a very emotional and engaging plot.
It could be just a random chant or repetition that someone has associated with the movie for no particular reason. Maybe it was part of a joke or a personal mnemonic device to remember something about 'Pulp Fiction'.
Since the details are scarce, Gary could be anyone. He might be an ordinary person living an extraordinary life as a gay man. Maybe he is a local figure in a community known for his contributions, or perhaps he is just a character in a story that is meant to represent certain aspects of the gay experience.