What do you think of these ideas? Feel free to use them; I hope you find them useful.
-A body swap (for example, Aemond with Lucerys, or Daemon with Otto).
-A girl from the modern day who ends up in the world of the series (where she is mistaken for a seer or a witch, among other things) and winds up starting a relationship with your favorite character—or trying to avoid one at all costs.
-Dragons taking human form through magic and causing trouble in the kingdom before returning to their original shape (a comical situation).
-Characters ending up in the modern day (for example, Aemond, Aegon, and Daemon); they must put aside their differences to survive.
-A modern man reborn as the son of Daemon and Rhea Royce; he uses his technological knowledge to create inventions and gain wealth and fame in the kingdom, and could even seek revenge against his father for his mother's death, among other possibilities.
Characters for the stories: Original Character, Daemon, Aemond, Daeron, and Ormund (since the last two are new to the series, there are few stories featuring them).
I’ll let you know if I come up with any more.
Cheers!!