Power dynamics can be explored in these fanfictions. Pirate Spain might have a certain amount of power as a pirate captain, and how that affects his relationship with the reader can be an interesting theme. For example, he could be protective, or there could be a struggle for control within the relationship. Additionally, the theme of redemption might be there if Pirate Spain has a troubled past that the reader helps him overcome.
One common theme is friendship. The relationship between the three characters can be explored in terms of how they become friends, support each other, and have fun together. Another theme could be cultural exchange, since Spain and Romano have their own distinct cultures in the Hetalia universe, and the reader can be a part of that exchange.
There are several platforms where you can find 'Pirate Spain x Reader' fanfiction. Archive of Our Own (AO3) is a great place to start. You can simply search for the tag 'Pirate Spain x Reader' and browse through the available stories. Fanfiction.net might also have some works, but AO3 generally has a wider range of content with better tagging and categorization.
Romance is also quite prevalent. It can range from a slow - burn relationship where the pirate and the reader gradually fall in love as they share experiences, to a more instant attraction kind of thing. And the cultural differences between a modern - day reader (if that's the case) and a pirate from England in the past can add an interesting dynamic to the relationship.
One of the themes is the celebration of their shared Mediterranean heritage. This might include elements like similar climates, love for the sea, and traditional festivals. Also, there can be themes related to art and history. Maybe a story where a Spanish artist is inspired by the art and architecture in South Italy, and that inspiration leads to a deeper connection between the two regions in the story.
In mermaid x pirate fanfiction, the theme of power dynamics often comes up. The pirate may initially have power over the mermaid as he captures her or has some advantage in their first encounter. But as the story unfolds, the mermaid's unique abilities can turn the tables. There's also the theme of loyalty. The pirate has loyalty to his crew, but his feelings for the mermaid can put that loyalty to the test. And finally, the theme of mystery. The mermaid's world and her abilities are often mysterious to the pirate, and this mystery drives the plot forward as he tries to understand more about her.
A great Romano x Reader x Spain fanfiction needs to capture the essence of the characters. Romano is known for his love of tomatoes and his pride in his heritage. Spain has his love for his country and his more carefree attitude. When the writer incorporates these traits into the story, it feels more authentic. Also, the relationship dynamics are important. The Reader should not be just a passive character but have their own agency. They could be the one who brings Romano and Spain closer or causes some drama between them. The story should also have a good pacing, not too rushed or too slow, so that the reader can fully immerse themselves in the world of the fanfiction.
Another theme could be historical trauma. Given their historical relationship, Spain's past actions during colonization or political control might be explored in fanfiction, with Romano still carrying the emotional scars of those times. This can manifest as Romano feeling hurt by Spain's presence or reminders of the past.
One idea could be a story where the male reader is a foreign exchange student in Spain. He meets Spain and they start exploring the local culture together, like going to flamenco shows, trying different tapas, and through these experiences, a deep friendship and then a romantic relationship develops.
One common theme could be cultural exchange. Given that Romano and Spain have different cultural backgrounds in the Hetalia universe, the crossdress aspect might add an interesting layer to how they interact culturally. For example, how Romano's perception of Spanish culture changes while in crossdress.
I'm sorry, I don't have specific fanfiction titles to recommend directly. But you can try searching on popular fanfiction platforms like Archive of Our Own (AO3). Use the tags 'Spain x Reader x Romano' and exclude the 'lemon' tag to find suitable stories.