One possible theme could be discovery. As I said before, if the lemon is some sort of new or magical object, the characters are on a journey of discovery about it. Another theme could be acceptance. If 'lemon' is a new character or concept, the other characters have to learn to accept it. For example, Amethyst might be more open - minded while others like Garnet or Pearl might be more skeptical at first.
The theme of transformation could be explored as well. The lemon could have the power to transform things or people in the Steven Universe world. This would force the characters, especially Amethyst and Steven, to adapt to these changes. It could also be a theme of creativity. Maybe the lemon inspires new forms of art or ways of thinking among the characters. They could use it to create something beautiful or useful, which in turn would enhance their lives in the Crystal Gem community.
A theme of growth is also possible. Through their interactions with the lemon - related element, the characters could grow. Amethyst might become more responsible or Steven might gain more confidence in handling new and strange things. And there could also be a theme of unity. If there's some sort of threat related to the lemon, the characters would have to come together, like the Crystal Gems always do, to face it. They would put aside their differences and work towards a common goal.
It could be about a unique adventure. Maybe Amethyst discovers a lemon - shaped magical object and she and Steven go on a journey to figure out its power. Since Amethyst is known for her wild and carefree nature, she might get into some comical situations while exploring the mystery of this lemon - related item with Steven.
There might be such a fanfic. The 'Steven Universe' fandom is quite large and creative. However, it's also possible that it doesn't exist. You could try searching on popular fanfic websites like Archive of Our Own or FanFiction.net to see if there's a story with this concept.
Adventure is also a common theme. They go on different quests or face various threats together. This could be something like exploring an ancient gem ruin on Earth or fighting off a new enemy. The theme of acceptance is important too. Accepting each other's flaws and differences. Amethyst accepting Steven's sometimes naive view of the world, and Steven accepting Amethyst's wilder side.
Friendship and family are also likely themes. In the Steven Universe world, relationships are important. The fanfics might show how the relationships between Pearl, Amethyst, and their gemlings form a sort of family unit or a strong friendship bond, dealing with the joys and challenges that come with it.
A common theme is innocence. Since she's a baby amethyst, the fanfictions often explore her naivete and how she discovers the world around her. Another theme is growth. It shows how she develops her gem powers and her personality over time. Also, the relationship with the Crystal Gems is a big theme, like how they protect and guide her.
A 'Steven Universe Amethyst Pregnant' fanfic could be a story that delves into the origin of the pregnancy. Is it some sort of magical or scientific anomaly? How does Amethyst feel about becoming a mother? She has always been the more carefree and fun - loving gem among the Crystal Gems. This new situation could force her to grow up in a way. It could also touch on the theme of family and what it means to create a new life within the context of the unique world of 'Steven Universe', exploring how the different species and cultures in the show interact with this unexpected event.
Another theme is adventure. For example, in fanfics like 'Amethyst and Steven's Epic Quests', they go on exciting adventures together, facing strange creatures and solving mysteries. This gives the writers a chance to create new and exciting worlds for them to explore.
One possible theme is growth. Both Peridot and Steven grow throughout the original series, and the fanfic could continue that growth in their relationship. They might learn to understand each other better and become stronger individuals as a result.
In Steven Universe fanfiction, the relationship between Steven and Amethyst can be really interesting. They are both very different characters. Steven is kind - hearted and has a strong sense of justice, while Amethyst is more of a free - spirited and somewhat rebellious character. In some fanfictions, their relationship might develop into a deep friendship where they support each other through different challenges. For example, Steven could help Amethyst come to terms with her insecurities about being a 'lesser' gem compared to the others.
One possible plotline could be that Lapis and Steven discover a hidden part of the Gem world together. They have to rely on each other's unique abilities to navigate through the challenges there. Another could be that Lapis is having trouble adjusting to life on Earth, and Steven helps her by showing her all the beautiful and positive aspects of the planet.