Yes, there are quite a few. You can start by looking on fanfic websites like Archive of Our Own. Some fanfics might focus on their adventures together on the Thousand Sunny, exploring how their different personalities interact during various situations.
Archive of Our Own (AO3) is a great place to start. It has a large collection of fanfics from various fandoms, including One Piece. You can simply search for 'Franky x Robin' in the search bar and it'll show you relevant stories.
Well, perhaps in the fanfiction, Franky and Robin's relationship deepens during an adventure on a new island. They find out about the pregnancy there. Franky might be a bit clumsy at first, like trying to build a too - big crib that takes up half of the living quarters. Robin would be the one to keep things in order. The crew would all pitch in to protect Robin during her pregnancy, with Sanji cooking special nutritious meals for her.
One interesting Franky fan fiction could be about his adventures before joining the Straw Hat crew. Maybe it details his time building those amazing inventions in Water 7. Another could be a story where Franky uses his skills to upgrade the Thousand Sunny in a completely unexpected way during a tough battle. And there might be a fan fiction that focuses on Franky's relationship with other crew members, like his bromance with Usopp and how they come up with new gadgets together.
Expect a lot of character exploration. Since Robin has a complex past and Zoro has his own goals and dreams, the fanfiction could delve into how they influence each other. For example, Zoro's pursuit of becoming the world's greatest swordsman might inspire Robin to pursue her own academic or personal goals more vigorously.
In Robin x Zoro fanfiction, their relationship can be really interesting. Robin is the intellectual and mysterious one, while Zoro is the strong and determined swordsman. Their interactions might start from a simple comradeship on the Straw Hat crew. Maybe in some fanfictions, Robin's knowledge could help Zoro in his swordsmanship journey, like providing him with historical information about some special swords or fighting techniques from the past.
Well, there are several places. Firstly, dedicated One Piece forums often have sections for fan fictions where you might find some great Franky - centric ones. Secondly, Reddit has some One Piece communities where fans share their fan fictions. Just search for 'Franky One Piece fan fiction' in those relevant subreddits. Also, some independent fan fiction blogs might have some unique and interesting Franky stories that you won't find elsewhere.
Many 'One Piece Robin x OC fanfiction' works explore the theme of acceptance. The OC, being an outsider in the One Piece world, has to be accepted by the characters, especially Robin. And Robin, with her own past, also has to accept the presence of this new character in her life. There's also the theme of growth, both in terms of power and character, for both Robin and the OC as they interact and go through various experiences together.
One common theme is adventure. Since they are part of the Straw Hat crew in One Piece, fanfictions often put them in new and exciting adventures together. Another theme is growth. Luffy and Robin both grow as characters, and fanfictions explore how they influence each other's growth. For example, Luffy's optimism might help Robin overcome her past traumas.
Perhaps in this fanfiction, Naruto is on a mission in his own world when a strange portal opens and leads him to the One Piece universe right where Robin is. At first, they are both cautious of each other. But as they learn about their respective powers and goals, they decide to join forces. Maybe there's a common enemy that is threatening both the ninja world and the pirate world, and together they strive to defeat it.