One popular trope is the 'enemies to lovers' arc. Since Hook and Emma had a bit of a rocky start in the show, many fanfictions explore how they overcame their initial differences and fell in love. It adds a lot of tension and drama to the story.
The 'hurt/comfort' trope is quite prevalent too. For example, when Hook gets injured and Emma takes care of him, or vice versa. It shows their deepening connection. Also, the 'time - travel' trope can be found, where they might go back in time and experience events that change their relationship in the present. This adds an interesting layer of complexity to their story.
The 'soulmate' trope is also quite prevalent. In these stories, Hook and Emma are often portrayed as being fated to be together, with some magical or supernatural force binding them. And of course, the 'hurt/comfort' trope, where one of them gets hurt and the other is there to comfort and heal them. This trope can add a lot of emotional depth to the stories.
One popular trope is the 'enemies to lovers' trope. Since Hook had a bit of a rough start with Emma, seeing their relationship develop from that initial animosity to love is quite common. Another is the 'soulmate' trope, where they are fated to be together. It gives a sense of destiny to their relationship.
The 'enemies to lovers' trope is really popular. Hook starts off as a bit of a scoundrel and Emma is distrustful of him at first. But as they spend more time together, they fall in love. Another is the 'soulmate' trope. Many fanfictions play with the idea that they are fated to be together.
One popular trope is 'Enemies to Lovers'. Captain Hook and Emma start off at odds with each other in the show, and fanfiction often plays on that dynamic, gradually turning their relationship into a romantic one. Another is 'Time Travel'. Writers might send Emma or Hook back in time, which changes the course of their relationship and creates new and interesting scenarios.
One popular trope is the 'friends - to - lovers' story. It often shows Xander and Emma starting as friends and gradually realizing their deeper feelings for each other.
I'm not sure of specific popular ones off - hand. But you can look at the most - read or highest - rated stories on fanfiction sites with the relevant tags.
One popular storyline could be about how they deal with the unexpected pregnancy in a world full of magic and danger. Maybe they have to protect the unborn child from villains who want to use its power. Another could be the emotional journey they go through, from shock to acceptance and finally to excitement for their new family.
One popular trope is the 'enemies to lovers' trope. Hook starts off as a bit of an anti - hero, so it's common to see stories where he and another character, often Emma, start off on the wrong foot but then gradually fall in love. Another is the 'time - travel' trope. Given the magical nature of the 'Once Upon a Time' universe, it's not unusual for fanfictions to involve characters traveling through time, which can create really interesting plotlines.
One popular trope is the 'protective Ray'. Since he's a rather intelligent and often calculating character, he's often depicted as being very protective of Emma in fanfictions. Another is the 'slow - burn romance'. Given their situation in the original story, their relationship might develop slowly over time, which is a common trope in fanfiction. And of course, the 'alternate universe' trope is also seen a lot, where they might be in a different setting, like a modern - day high school or a fantasy world.