So let's get into it!
1) I would love a retelling of The Little Mermaid because there are not enough mermaids in YA. It's also a lot darker in the original so I think that'd be interesting! There are lots of characters and dynamics that could work well with YA if it was loosely retold. It doesn't even have to be about mermaids , the author could take the 'mermaid who wants to be a human' thing as a metaphor!
Beast is such a beautiful and powerful story that there is a lot you could do with it while retelling! It could literally be a beast or maybe someone who believes that they are a beast. There are so many different version that could be wonderful!
3) I think that the story of Aladdin could fit into the typical YA story. I can definitely imagine a retelling of that with lots of magic!
4) Recently I've been really interested in Arthurian Legends. We discussed this in last weeks UKYA Chat and a lot of people would love to see those stories made into a YA novel! How cool would a story about Merlin ,King Arthur , Lancelot , Guinevere and all of that stuff?
5) There are so many Celtic legends that I would love to see retold. They're rarely modernised so someone should bring them back!
6) More stories from the POV of the common villains! Why did they go out of their way to destroy the life of the protagonist? Do you feel sorry for them or are they just completely insane? What about their past? Did something terrible happen to them , causing them to lose faith in life and happiness? Is there any part of themselves that is human?
That is all of the fairy tales and legends that I can think of right now. What are your favourite fairy tales? Have a good day!