One concept that often shows up in Wish Realm fanfiction is the blurred line between reality and fantasy. The Wish Realm is a place where dreams and wishes can become real, but at what cost? It can be used to explore themes of greed and self - discovery. Also, the idea of a Wish Realm guardian or keeper who has their own motives and agendas for allowing or denying wishes is quite interesting.
I'm not sure of specific titles off the top of my head, but you can check out fanfiction websites like Archive of Our Own. There are likely many Once upon a time Wish Realm fanfictions there. Look for ones with high ratings and lots of reviews as those tend to be more popular and well - written.
One idea could be exploring the backstories of the lost boys in more detail. Maybe one of them has a hidden connection to a character from the outside world. Another plot could involve a new villain coming to Neverland who has a different kind of magic that challenges Peter Pan. Also, a story about Wendy's granddaughter returning to Neverland to find a lost family heirloom could be interesting.
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.
One interesting crossover could be Hermione finding herself in the Once Upon a Time world. She might use her magic skills to solve the strange problems there. For example, she could help the characters break a particularly difficult curse using her vast knowledge of spells. Another could be her interacting with the fairy - tale characters like Snow White or Cinderella. She could teach them about the more advanced forms of magic she knows from the wizarding world.
One interesting crossover could be Naruto characters in the Once Upon a Time world facing magic they've never encountered before. For example, Naruto might be intrigued by the dark magic in Storybrooke. He could use his own chakra powers in unique ways to combat it or understand it better. Another idea is having characters from Once Upon a Time learn ninja techniques from Naruto. This would change the power dynamics in their own fairy - tale world and create new storylines.
In Frozen Once Upon a Time fanfiction, a common theme is the redemption of characters. Maybe a character from Once Upon a Time who was a villain gets a chance at redemption through their encounter with the Frozen characters. Also, the theme of family is important. The strong family bonds in Frozen can be contrasted or combined with the often - complex family relationships in Once Upon a Time. Additionally, the idea of time - travel or alternate timelines can make for some really interesting fanfictions as it allows for new and unexpected interactions between the two universes.
Well, a really cool crossover idea is to combine the powers of Scarlet Witch with the magic in 'Once upon a time'. Scarlet Witch's reality - warping powers could be seen as a form of powerful magic in a fairytale world. She could accidentally open portals to fairytale lands and the Avengers have to deal with the consequences. Also, Thor could be seen as a god - like figure in a fairytale world, similar to some of the all - powerful beings in 'Once upon a time'. His hammer could have even more magical properties in this crossover, and he might have to prove himself worthy in a different way, like by solving a riddle in a fairytale - like trial.
Well, you could create a 'once upon a time parody fanfiction' where the magic in the fairytale world is actually just advanced technology that the characters don't understand. For instance, the fairy godmother's wand could be a high - tech device from a more advanced civilization. Also, you could make the villains into bumbling idiots instead of the menacing figures they usually are. This would add a lot of humor to the story.
One idea could be exploring Drizella's backstory before she became so bitter. Maybe she had a true love in her youth that was torn away from her, which led to her descent into jealousy and meanness.
One popular Once upon a time slash fanfiction could be about Captain Hook and Rumplestiltskin. Some fans like to explore their complex relationship in an alternate romantic or deeply emotional way. Another might be centered around Emma Swan and Regina Mills, imagining a different kind of bond between the two strong female characters.