There is quite a lot of choice & variety.
To only mention a handful of public domain classics: Grimm's Fairy Tales are an obvious choice (think Sbnow White, Cincerella, Hansel & Gretel and so, so many more (quite hardcore to be honest), Lewis Caroll's Alice's Adventures in Wonderland, Barry's Peter Pan or even things like Ovid's Metamorphosis (hard to beat, imho, even if many won't like it being categorized as a fairy tale and would prefer 'mythology'). Talking mythology, one coudl also consider reading some Norse mythology (the 'Edda', and sagas), and so on.