Friendship is a very common theme. Many fanfictions focus on how Jake and Albert form a strong bond, whether it's through shared experiences or helping each other out in difficult times.
Love is a very common theme. The stories often revolve around the developing relationship between Jake and the reader, from the initial attraction to deep, committed love.
A common theme is the clash of different personalities. Rattlesnake Jake is often portrayed as tough and menacing, so when paired with an original character (oc), there can be a lot of friction and then growth in their relationship. Another theme is adventure. They might go on a journey together through the wild west - like settings.
Romantic undertones are also quite common. Some fanfiction writers like to explore a potential romantic relationship between Rich and Jake. This could involve them slowly realizing their feelings for each other, dealing with the confusion and excitement that comes with new love, and how it affects their friendship and their lives within the context of the Be More Chill world.
One great Jake x Albert fanfiction is 'The Unlikely Bond'. It beautifully explores their friendship in a unique setting. The story shows how they overcome challenges together and grow closer as characters.
Protection could be a common theme. Since the reader is pregnant, Albert Wesker might be portrayed as being very protective of her. Maybe he uses his skills and power to keep her and the unborn child safe from various threats.
In Cyborg 009 Albert x Joe yaoi fanfiction, a frequent theme is the forbidden nature of their relationship. In the original setting, they are comrades with a certain set of relationships, and exploring a romantic or yaoi - type relationship can add an element of taboo. Also, themes of sacrifice and mutual understanding often come up. Their different backgrounds and abilities can lead to situations where they have to sacrifice for each other or understand each other's limitations, which can be deeply explored in fanfiction, especially in the context of a yaoi relationship.
The theme of redemption can also be found. For example, if in the fanfiction Tsu'tey has some misgivings about Jake at first, he may later find a way to redeem himself in Jake's eyes and vice versa. This adds depth to their relationship and the overall story.
One common theme could be friendship. They might explore how Dwight and Jake become friends, what they bond over, and how their friendship grows. Another theme could be adventure. Maybe they go on some kind of adventure together in the fanfic.
Some fanfictions might also focus on character development. Writers could show how Candy and Albert grow as individuals within the story. Maybe Candy becomes more confident or Albert learns to be more empathetic. These changes in their personalities can be an important part of the fanfiction and can be intertwined with the relationship between them, whether it's a romantic or a platonic one.
Love is a very common theme. Their deep and abiding love for each other is often explored in great detail. Another is the theme of royalty and the duties that came with their positions. Fanfictions usually show how they balanced their love and their royal responsibilities.