The theme of discovery is also prevalent. Steven discovers more about the Diamonds through his encounter with Pink Diamond, and Pink Diamond might discover new things about Earth and the Crystal Gems. There's also the theme of family, as Steven's connection to the Diamonds is a sort of family - related one, and this meeting can further explore that aspect.
A major theme is often power. As Pink Diamond, Steven has a different level of power and influence. Fanfictions might explore how he uses or misuses this power. Also, relationships are a big theme. His relationships with the Crystal Gems, his human friends, and even his enemies might change because of his new identity. For instance, his relationship with Garnet could be affected as she was made in part by Pink Diamond. There could be a lot of emotional turmoil and growth in these relationships.
One interesting idea could be the cultural exchange between Pink Diamond and Steven. Since they come from different backgrounds within the Gem world, their meeting might lead to a sharing of unique abilities and knowledge.
One possible plot could be that Steven, having heard so much about Pink Diamond, finally has a chance encounter with her in a dream-like realm. They start to talk about the past, how Pink Diamond used to view the Earth and her complex relationship with the other Diamonds. Steven tries to understand her better and in the process, Pink Diamond gets to see how much the Earth has changed and how her actions still have an impact today.
Often, it portrays their relationship as one of mutual understanding. Steven, being empathetic, tries to understand Pink Diamond's past and her motives. Pink Diamond, in turn, may be intrigued by Steven's unique existence.
There's this 'Steven meets Pink Diamond fanfiction' called 'The Diamond Dialogue'. In it, their meeting is filled with revelations about the past of the Diamonds and Steven's role in the whole story. It has an interesting plot that keeps you hooked as they exchange thoughts and feelings.
Obviously, Steven and Pink Diamond are the main characters. Steven, with his unique ability to understand and empathize with all beings, and Pink Diamond, with her complex and mysterious past. Their interaction would be the core of the fanfiction.
Power and responsibility is also a theme. Given that Steven has unique powers and Blue Diamond has her own vast power and influence. Fanfictions often explore how they use or should use their powers and the responsibilities that come with them. In some stories, they work together to solve problems that require both of their powers and the right mindset to take on the associated responsibilities.
Well, it depends on what you're looking for in a fanfiction. Some 'Steven is Pink Diamond' fanfictions are more action - packed, with Steven using his new - found power and status to fight against new threats. Others are more character - study - like, delving into his internal struggles and how he copes with being Pink Diamond. You really have to dig in and read a few to find the ones that suit your taste.
Perhaps the fanfiction could start with Steven having a strange dream about Pink Diamond. When he wakes up, he starts to notice small changes in himself, like his gem glowing pink more often or having strange new abilities. As he becomes more and more like Pink Diamond, he realizes that there is a connection between his mother and himself that he never fully understood. He then embarks on a journey to discover the truth about his transformation, along the way facing challenges from both the Homeworld and Earth - based gems who are either afraid of or intrigued by his new form.
In 'pink diamond time travel fanfiction', a recurring theme is the mystery surrounding the diamond's time - traveling ability. Writers often explore how and why the pink diamond has this power. Another theme is the interaction between the diamond and different cultures throughout time. For example, how it is perceived in ancient civilizations compared to modern ones. There is also the theme of love and friendship that develops as characters travel through time with the pink diamond. The shared experiences create strong bonds between them.