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.
Franky stands out in the One Piece manga for his cyborg enhancements and his passion for building crazy ships. His loyalty to the Straw Hat crew is also a defining trait. Plus, his outlandish appearance and catchphrases make him memorable.
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.
One of the best stories about Brook is his backstory. Brook was a part of the Rumbar Pirates. When they were poisoned, Brook watched his crewmates die one by one. His own death was followed by his soul wandering for decades until he found his body again. This shows his long - suffering and his loyalty to his old crew, which is really touching.
One interesting Brook OC fanfiction could be where an original character joins Brook's crew on a musical adventure across the Grand Line. They might discover new islands with unique musical cultures and instruments.
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.
Their relationship could grow stronger as they face the challenges of pregnancy together. Franky would become more protective, using his mechanical skills to ensure Robin's comfort. For example, he could build a special chair for her. Robin would rely on Franky more, sharing her fears and hopes for their future family.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of One Piece fanfictions, and you can search specifically for ones related to Brook and original characters (OCs).