Friendship is a very common theme. They are both important characters in the Shadowhunter universe, and many fanfictions explore how they become friends and support each other.
Another common theme is growth. Both Clary and Alec grow as characters throughout the series, and fanfictions often continue this growth. For example, they might learn new skills or gain a deeper understanding of their powers and roles, and how that affects their relationship with each other.
One common theme could be betrayal. Alec might be in a situation where he has to betray Clary for some reason, like loyalty to his own group or family, which causes her harm.
A theme that also pops up is the discovery of new sides of each other. Clary and Alec each have their own personalities and secrets. Fanfictions often explore how they learn more about each other, which in turn strengthens their bond. For example, Alec might discover a more vulnerable side of Clary, and vice versa.
One common theme is the adjustment of their relationship. With the pregnancy, they need to redefine their roles and how they interact. Another theme is the support from their friends and family. In many fanfictions, their friends play an important part in helping them through this new chapter.
Love and commitment are common themes. Their marriage is a new chapter, and fanfictions often explore how they stay committed to each other in the face of various difficulties.
One common theme is friendship. Many fanfics explore the deepening of the friendship between Alec and other characters. For example, how Alec and Clary become closer friends over time and support each other through various difficulties.
One common theme is family. Since they both have complex family backgrounds in the Shadowhunter world, their married life often involves dealing with family issues. For example, how their families interact with each other.
Well, one common theme could be the exploration of their relationship in more intimate or romantic settings. Another might be the development of their characters within those scenarios.
They are popular in fanfiction because they both have such strong and distinct personalities. Alec is the stoic and responsible leader, while Clary is the brave and creative new addition to the Shadowhunter world. Their interactions can be full of tension, drama, and also the potential for great friendship or more, which is very appealing to write about.
There's also 'Alec and Clary: A Different Path'. In this one, they accidentally end up in a parallel dimension where they have to rely on each other more than ever. It's a short but exciting read that really shows their growth as characters and how they can support one another.
Overcoming obstacles is another theme. Fanfictions often show Maurice and Alec dealing with the social and family barriers that come their way. For example, in some stories, they have to face the disapproval of Maurice's family, but they still hold on to each other.