You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of fan - made stories, and you're likely to find some great 'uta x luffy fanfic' there.
Some dedicated One Piece fan communities might also have their own collections or recommendations of 'uta x luffy fanfic'. You can join forums or groups related to One Piece and ask the members for their favorite stories in this category.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfics from various fandoms, including One Piece, so there's a good chance you'll find some luffy x uta fanfic there.
Fanfiction.net is also a great place to find luffy and uta fanfiction. There are many talented writers who post their works there. However, the website's interface might be a bit old - fashioned compared to AO3. But it still has a good amount of content related to different anime and manga pairings, including luffy and uta.
Some 'uta x luffy fanfic' could explore a scenario where Uta joins the Straw Hat crew. This would bring a new dynamic as her musical powers and her connection to Luffy would add interesting plotlines. For example, she could use her music to enhance the crew's morale during tough battles.
There could be a luffy x uta fanfic where they meet in a different timeline. Uta's singing might have a special effect on Luffy, giving him new powers or a different perspective on his goals. This would lead to an interesting exploration of their relationship and how it affects the world around them.
You can try some popular fanfic websites like Archive of Our Own (AO3). It has a large collection of fanfictions on various topics, including reiju x luffy. Just use the search function there and you might find some interesting reads.
Their relationship could start with Uta being initially distrustful of Luffy. After all, Luffy is a pirate and Uta has her own ideas about pirates. But as she sees Luffy's pure heart and his determination to protect his friends and pursue his dreams, she starts to warm up to him. They might then become friends who share their different stories and experiences.
Another place to check is Wattpad. There are many fanfiction writers on there who write about different pairings, and 'uta x reader' is likely to be among them. Browse through the different categories or use the search function to find what you're looking for.
Fanfiction.net is also a good place to look. There are tons of One Piece - related fanfics on it. Just use the search function and type in 'luffy x nico robin' to find relevant stories. However, the quality can vary, so you might need to do a bit of sifting through.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of One Piece fanfics, and you should be able to find some great boa x luffy ones there.
Fanfiction.net could also be a good place to search. It has a wide range of fanfictions. However, the quality can vary a lot. So you may need to spend some time filtering through the results. Check the ratings and reviews if available to find the better sanji x luffy fanfics.