Another theme could be 'unexpected love'. In many of these fanfictions, the kiss might come as a complete shock to both characters and those around them. It can lead to a lot of confusion, self - discovery, and changes in the group dynamics among their friends. For example, Leonard might be very surprised and have mixed feelings about it, which can add more drama to the story.
One common theme is friendship. Since they are such different characters in the show, it's fascinating to see how fanfiction writers develop their friendship. For example, Penny might teach Sheldon about social norms while Sheldon might introduce Penny to some scientific concepts in a fun way.
One common theme is the growth of their relationship. Writers often explore how Penny and Sheldon move from being just neighbors and friends to something more. Another theme is the clash of their different worlds. Penny, the actress, and Sheldon, the scientist, have very different lifestyles and interests, and fanfictions often play with how they navigate these differences.
One common theme is the idea of opposites attracting. Sheldon is very logical and Penny is more emotional and social, so many fanfictions play on how these differences can draw them together. For example, in some stories, Penny helps Sheldon understand emotions better, while Sheldon helps Penny with intellectual things.
One common theme is friendship development. Fanfictions often focus on how their relationship grows from being just neighbors to really good friends who understand each other's quirks.
The theme of growth is also common. As they fall in love, they both grow as individuals. Sheldon might become more in tune with his emotions, and Penny might become more patient. Another theme is the reaction of their friends. Their friends' opinions and reactions often play a big part in the story.
A frequent theme is the evolution of their relationship. It might start from friendship or just a simple attraction and develop into a deep, loving connection. Also, the theme of acceptance is quite common, as Sheldon has his quirks and Penny has to accept those, and vice versa, in the fanfictions.
The theme of discovery is often present. Penny discovers new aspects of Sheldon's personality that she hadn't noticed before, and vice versa. For instance, Sheldon might discover Penny's hidden intelligence or her capacity for deep emotional connection. This discovery process helps to build a stronger bond between them in the fanfiction, and it also adds an element of intrigue and development to the story.
There are various platforms where you can find such fanfiction. Archive of Our Own (AO3) is a great place to start. Just type 'Sheldon kisses Penny' in the search bar, and you'll get a list of relevant stories. However, the nature of fanfiction can vary greatly in terms of writing quality and the direction the plot takes.
One common theme is the growth of their relationship. Their friendship or potential romantic relationship evolving over time, with Penny helping Sheldon become more social and Sheldon introducing Penny to new intellectual concepts.
Character development is also a big part. For example, Penny might help Sheldon grow in his social skills while Lemon could influence their group dynamics in a new way. The fanfictions often play with the relationships between the three characters, showing how they can support or annoy each other in different scenarios. And they also tend to be set in the familiar Big Bang Theory - like settings, which gives a sense of familiarity to the readers.