It's difficult to say the common themes without reading a lot of it. But it could potentially include themes like adventure if 'the star in yellow' is a character in a fantasy - type setting. Or it might have themes of friendship if it involves a group of characters associated with 'the star in yellow'.
Since we don't know much about 'the star in yellow' specifically, the themes could be quite diverse. If it has a science - fiction element, then perhaps exploration of new worlds or technologies could be a theme. Another possible theme could be self - discovery if the main character (the star in yellow) is on a journey of some sort within the fanfiction.
If Ash and Yellow are from a post - apocalyptic world in the fanfiction, survival themes would be prominent. They might have to fight against mutated creatures, find food and shelter, and also deal with other survivors. Additionally, themes of hope and rebuilding society could also be part of the 'ash and yellow fanfiction' as they strive to make a better world in the ruins.
One common theme is friendship. Red and Yellow often form a strong bond in these stories, just like trainers do in the actual Pokemon games. Another theme is adventure. They go on journeys, explore new regions, and discover new Pokemon species.
One common theme is the growth of the characters. Red and Yellow often start as novice trainers and develop their skills and relationships with their Pokemon throughout the story.
One common theme is their relationship dynamic. Given their positions in the Diamond Authority, many fanfictions explore how they interact with each other, whether it's in a power - struggle sense or a more collaborative way.
One common theme is the underdog story. A trainer who starts off weak but grows stronger. Another is friendship, like the bond between a trainer and their Pokemon. Exploration of the Kanto region is also a big theme, as it is such a rich and iconic setting in the games.
One common theme is their relationship repair. Given their complex relationship in the show, fanfictions often explore how they might overcome their differences and become closer. For example, some stories might have them having heart - to - heart conversations and understanding each other better.
One common theme could be the budding romance between the main character (the trainer) and a particular Pokemon. Another might be a romantic encounter between different trainers within the Red and Yellow game world.
One common theme is friendship. Just like in the original Pokemon concept, the friendship between the Trainer and their Pokemon is often emphasized. It can be shown through how they support each other in tough situations.
Since Naruto has themes like perseverance, growth, and bonds, and Yellow Diamond (assuming from Steven Universe) has themes related to leadership and power, in a lemon fanfiction, there might be themes of forbidden or intense relationships. Maybe the characters from both series come together in a situation where they have to overcome differences in a rather steamy way. However, this is just speculation as it's not a common or widely - studied combination of fanfiction.
One common theme could be the defeat and injury of Pokémon in battles, perhaps more brutally than in the original game. Another might be the emotional hurt of the trainers, like when they lose their Pokémon or face betrayal from other characters in the fanfiction world.