Fanfiction exists in a bit of a complex legal space. Generally, reading or enjoying Once Upon a Time fanfiction in its normal forms (text or fan - made audio) is legal. But if there are elements that seem to be overly exploiting the original show's brand or are causing confusion in the market as if it were an official spin - off, there could be legal issues. But overall, for the most part, it's legal to engage with fanfiction.
One common theme is time -travel. Since both shows deal with different timelines in some way, fanfictions often explore more about time -travel and how it affects the characters. For example, a character might go back in time to change a crucial event.
You can try fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. These platforms have a vast collection of fanfictions from various fandoms, including those related to 'Once upon a time' and 'Watch the future'. Just use their search functions to look for the specific fanfictions you're interested in.
Family relationships are a big theme. Some fanfics focus on the family dynamics between characters like the Charmings and their descendants. There are also fanfictions that revolve around the theme of identity. Characters in 'Once upon a time' often have complex identities, and fan writers like to dig deeper into how these identities are formed and how they can change over time.
Some independent blogs or personal websites dedicated to Once Upon a Time might also host fanfictions. You can find these by doing a simple Google search. For example, search for 'Once Upon a Time fanfiction blog' and explore the results. But be careful as the quality and legality of the content on some of these sites might vary.
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.
Begin by choosing your favorite characters from 'Once upon a time'. Decide if you want to focus on one character's story or a group of them. After that, plan out the plot. You can make a simple outline of the beginning, middle and end. Consider the setting, whether it's the Enchanted Forest or Storybrooke. Also, think about the tone of your fanfic. Do you want it to be light - hearted, dark, or something in between? Once you have these elements in place, just start writing. Don't worry too much about making it perfect at first, you can always edit later.
You can try websites like Fanfiction.net or Archive of Our Own (AO3). Fanfiction.net has a large collection of fanfics from various fandoms, including Once upon a Time. Just use their search function and type in 'Once upon a Time'. AO3 is also great as it has a well - organized tagging system, making it easier to find specific types of Once upon a Time fanfiction, like those focused on a particular character or relationship.
One common theme is the exploration of alternate timelines. Since 'twice upon a time' implies a doubling of the story - perhaps one that already exists in the 'once upon a time' framework - fanfiction often delves into how different choices in these two timelines can lead to vastly different outcomes for the characters. Another theme could be the redemption of characters. In these types of fanfictions, characters who might have been villains in the original 'once upon a time' setup could get a second chance in the 'twice upon a time' scenario to change their ways and become heroes or at least more morally ambiguous figures. Also, the theme of lost love and its rekindling is popular. Maybe a couple was separated in the 'once upon a time' but are reunited or have a chance at a new relationship in the 'twice upon a time'.
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.
Fanfiction is a bit of a grey area legally. Technically, most fanfiction is created without official permission from the original creators of JoJo. However, as long as it's not being used for commercial gain and is more of a fan - made homage, it's generally tolerated. So, in the sense of reading (not really 'watching' as it's text) it's not typically actively prosecuted, but it's not fully legal in the strictest sense either.