In this kind of fanfiction, the 'forced partnership' trope is quite popular. This is when two characters from Once Upon a Time and Descendants are forced to work together, despite their differences. For instance, a hero from Once Upon a Time has to team up with a villain - in - training from Descendants. Another popular trope is the 'culture clash' trope. Since the two shows have different settings and cultures, it's interesting to see how characters react when exposed to the other's way of life. And the 'mystery object' trope is also seen often, where a magical object from one world ends up in the other and causes all sorts of chaos and adventure.
A common trope is the time - travel trope. Maybe a character from Once Upon a Time travels to the Descendants' world in the future or vice versa. Family reunions are also popular, especially when characters from the two shows discover long - lost family connections. And of course, the 'hidden power' trope, where a character discovers a new and unexpected power when they enter the other show's world, which they then have to learn to control.
One popular trope is the fish - out - of - water. When the Descendants characters are brought into the Once Upon a Time world, they're like fish out of water. For example, the VKs (Villain Kids) from Descendants are used to the Isle of the Lost, and in Storybrooke or other OUAT settings, they have to adapt to a whole new set of rules and cultures. Another is the family connection trope. Since both shows have characters based on fairy tales, finding out new family relations between the two universes is a common and interesting trope. For instance, if a Descendants character is related to an OUAT character in a way not explored in the original shows.
A 'found family' trope is quite common. Characters who were alone or estranged in the show form a close - knit family in fanfiction. For instance, Henry might bring together different characters who then become his new family. Also, the 'hurt/comfort' trope, where a character is hurt (physically or emotionally) and another character comforts them, is frequently used in Once upon a Time fanfics.
A prevalent trope is the 'reincarnation' trope. Fans might write about how the characters are reincarnated in different time periods or worlds and how their relationships are rekindled. 'Power - swapping' is another interesting one, where characters exchange their powers and how that affects their relationships and the story. There are also 'secret relationship' tropes, especially for characters who had a lot of chemistry on the show but never got together officially, like Belle and Will Scarlet. Writers create scenarios where they have a secret relationship and all the drama that comes with it.
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 'forbidden love' trope. In 'Once upon a time', there are so many different storybook characters from different worlds and with different statuses, so a relationship between two characters who are not supposed to be together, like a princess and a villain, is quite common in the fanfiction. Another is the 'reunion' trope. Since many characters have lost their memories or been separated in the show, fanfiction often features them reuniting and falling in love all over again.
One popular trope is the 'destined to be together' for the main characters. It often involves a complex relationship between hunters and supernatural beings. Another is the 'found family' trope, where a group of misfits come together to fight against evil. And the 'hidden power' trope, where a character discovers they have a special ability they didn't know about before.
One popular theme is the relationships between the different characters from 'Descendants' and how they might interact with characters from 'Once upon a time'. For example, how Mal from 'Descendants' would get along with Snow White from 'Once upon a time'.
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.
Another common trope is the 'Time Travel' trope. Given the magical nature of the 'Once Upon a Time' universe, it's not surprising that many fanfictions use time travel as a plot device. For example, Emma or Hook might travel back in time to change an event that affects their relationship, or they could be sent to the future and have to deal with the consequences of what they see there in relation to their love for each other.
In 'Descendants' fanfiction, a common theme is the integration of the villains' kids into Auradon. It's about how they adapt to a new life. For 'Once Upon a Time', time - travel and alternate universes are quite popular. For example, stories where characters go back in time to change certain events in the fairy - tale world.