Yes, there are. A good place to find them is by joining One Piece - related fan forums. People often share and recommend their favorite fanfics there. The Robin x Aokiji pairings in fanfics can offer interesting takes on their relationship, such as exploring how Robin's intelligence and Aokiji's laid - back yet powerful nature could create an interesting dynamic.
I don't have enough context to determine exactly who 'garp' is. It could be a newly created character by the fanfic writer, or it might be a character from a relatively unknown story that is being incorporated into the 'ace fanfic'.
There are several factors. Their different personalities and the potential for character development in a fanfic setting. Robin's past traumas and her search for knowledge contrast with Aokiji's more easy - going but still complex personality. Writers can explore how they influence each other, and how their relationship could evolve over the course of a story. Additionally, the world - building opportunities in a Robin x Aokiji fanfic are great, as they can be placed in various locations in the One Piece world and interact with different characters, all while their relationship is at the center of the story.
Their relationship could start with distrust. Aokiji being a former Marine and Robin being a wanted archaeologist. But as they interact more, they might find common ground in their search for truth. Maybe they start to share stories about their pasts, which slowly builds a bond between them.
A 'aokiji wins fanfic' is essentially a piece of fan - created fiction focused on Aokiji's victory. Fanfics are often written by fans who want to explore different possibilities for their favorite characters. In this case, Aokiji could win in various ways. He might outwit his opponents, or he could have some sort of new power - up that allows him to win a difficult situation. It could also be a story where he wins the hearts of the people around him, becoming a more respected and beloved character in the fan - created narrative.
Aokiji Robin fanfics often focus on their contrasting personalities. Aokiji is usually depicted as calm and detached, while Robin is more mysterious and knowledge - hungry. So, these fics play with how they interact given these differences.