Another option is to join Undertale - related forums or communities. People there often share and recommend good fanfictions. For example, on the Undertale subreddit, you can post a request for undertale sans x underswap papyrus fanfictions and I'm sure the community will be happy to help.
There is 'The Star' by H.G. Wells. In this short story, an astronomer discovers that a star is actually a supernova, and the implications of that discovery for religious beliefs are explored. Then there's 'Tau Zero' by Poul Anderson, a story that takes the reader on a wild ride through space and time as a spaceship tries to outrun the expansion of the universe.
One possible plot could be that Harry discovers his connection to Nightwing in a mysterious way. Maybe he starts having strange dreams or finds an old artifact that reveals the truth. Then he has to learn to balance his wizarding world life with this newfound heritage related to Nightwing, which could bring in new powers and a whole new set of challenges.
Joanna Beauchamp is another important character. She is an experienced witch, a mother figure who has a lot of knowledge about their magical heritage and tries to protect her family.
I'm not sure who specifically is named the 'empress of never ending story' as it could be a very specific or fictional concept within a particular game, book or someone's personal creation.
Some Halo - related forums might also be a good source. There are often fanfiction sections where users share their own works. For example, the official Halo forums or some dedicated Halo fan communities. You might have to do a bit more digging there, but you could discover some hidden gems that haven't been posted on the bigger fanfiction platforms.
One idea could be to create a fanfic centered around a new Jedi character. This Jedi could be from a previously unexplored planet in the Star Wars universe. They start their journey, facing the classic struggle between the light and dark side of the Force, and encounter well - known Star Wars species along the way.
The main plot of 'Jimmy Valentine' is about a reformed safecracker. Jimmy has just been released from prison and is determined to go straight. However, his past catches up with him when he has to use his safecracking skills one last time to save a child trapped in a bank vault.
Family - centered stories that are positive can create a sense of unity. For example, stories about a family working together to build a new home can inspire family members to collaborate. They learn that by pooling their resources and efforts, they can achieve great things. It also gives a feeling of belonging as everyone is part of the same journey.
Another one could be 'Love's Surprise Kiss'. This fanfiction shows how a spontaneous troyler kiss can change the entire dynamic of their relationship. It's a sweet and unexpected moment that readers find really endearing.