One common theme is the crossover aspect. Writers often explore how the two different universes (Buffyverse and Twilight - verse) collide. For example, how Xander would react to the vampire world of Twilight or how Edward would deal with the demons in Buffy's world.
Another theme could be friendship or rivalry. Some fanfictions might focus on them becoming friends and teaming up against common enemies. Or they could be rivals, perhaps competing for the affections of a certain character. There's also the theme of self - discovery. Both characters have their own insecurities and issues, and in fanfiction, they might go through a journey of self - discovery while interacting with each other. They could learn from each other's strengths and weaknesses, which makes for an interesting read.
You can try some popular fanfiction websites like FanFiction.net or Archive of Our Own (AO3). They have a vast collection of fanfictions, and you can simply search for 'Xander Harris Edward Cullen' in their search bars to find relevant stories.
Power - up is a very common theme. Xander goes from being the 'normal' one in the group to having some extraordinary powers or skills. Also, friendship is often explored. His relationships with Buffy, Willow, and the others are either strengthened or tested as he becomes a bamf. In some stories, his newfound status makes his friends see him in a whole new light, which can be both positive and negative for their friendships.
Another theme is the battle between good and evil. Angel is a vampire fighting for good, and Xander is often involved in the fight against the forces of darkness in Sunnydale. Fanfictions may show how they combine their strengths, Xander's street - smart knowledge and Angel's supernatural abilities, to combat evil.
In 'Game of Thrones Xander Harris fanfiction', a frequent theme is the exploration of power dynamics. Xander, being a new element in the 'Game of Thrones' world, has to navigate the complex web of power that exists among the different houses and factions. He might start as a nobody but gradually rise through the ranks, or he might be used as a pawn by those in power. Another common theme is the struggle between good and evil. Xander could be a force for good in a world full of corruption and violence, or he might be tempted by the dark side of power, much like many characters in 'Game of Thrones'. Also, the theme of identity is often explored as Xander has to figure out who he is in this new and dangerous world, while still holding on to his roots from his own world.
Well, often you'll see themes related to the actor's real - life influence on the character. For example, if the actor has a particular hobby or trait, it might be incorporated into how he portrays Edward Cullen. The theme of the actor's growth throughout the filming process is also common. As he films more scenes, how does he change as an actor? And of course, there are fanfictions that focus on the actor's love life outside of the Twilight world, comparing it to Edward Cullen's romantic story.
Love is also a major theme. Just like in the original Twilight series, the Edward Cullen character, even as an alien, falls in love with a human. It's about the challenges and beauty of an inter - species relationship.
One common theme is self - discovery. Since Edward was in a heterosexual relationship in the original Twilight story, in gay fanfiction, he often has to rediscover himself and his feelings. Another theme is acceptance, both self - acceptance and acceptance from others like his family. Love and passion are also common themes, just like in any relationship - based fanfiction.
One common theme is the exploration of their eternal love. Writers often expand on how their love endures through different challenges. Another theme is the power dynamics, especially considering Edward's vampire nature and Bella's human - turned - vampire state in some stories.
One common theme is the exploration of cultural differences. For example, how different holidays or traditions are shared between the characters. Another theme is the facing of prejudice. Since it's an interracial relationship in the context of the Twilight universe, they often have to deal with the stares and whispers from others.
Another theme is self - discovery. As a human, Edward has to figure out who he is without the allure and power of being a vampire. He might question his own values, his place in the world, and what he really wants to do with his life. This often leads to a journey of self - exploration and growth in the fanfiction stories.