A friend of mine once said "They've mined the Kalevala for ideas and themes for decades. You never heard of the Moomins?"
I find that even bad fantasy can spark ideas and drive scenarios.
*holds up The Hunger Games* See this? *holds up a Twilight book* And this? *holds up some Harry Potter books* And these? *hurls them across the room as far as they can go* I have an idea. Let's do something that is NOT that!
This is going to sound dreadfully heretical, but if you want to create original fantasy, you are going to have to throw the fantasy books away. All of them. Including the mythologies. Indonesian, Japanese, Finnish, Australian Aboriginal, Italian, Russian, Dutch - whichever nation you pick, there's some Disney executive sitting in a library somewhere, snapping pics of pages upon pages of that nation's myths and legends.
Expect a Brave 2 set in Ireland next time, a Frozen 2 set in the Caribbean, a Baba Yaga set on the Russian Steppe ... you think of it, and they'll end up doing a segment of Once Upon A Time or a Disney movie out of it.
You want to create. Create. Drop the mediaeval tropes. Set your stories off the Earth. Tell stories of a place called Land's End, where there's a cliff nobody goes to - a place where the world falls away to infinity. Go to your dreams. If you dreamed of an ancient city flying in the sky, have your characters try and seek it out by travelling the world in sputtering old vintage automobiles.
Do you want a post-apocalypse Legend
? Let the End of The World look completely different to the Mad Max scenario you might be familiar with. What would the End of the World look like to the ancient Minoans? Archaeologists know what it looked like - fifty years of pillaging by Peloponnesian Greeks until there was little or nothing left of them. What about setting the End of The World at the time of the fall of the Indus Valley civilisation, only in this historical time frame, there are no other humans left anywhere on the planet. A fungus would do the trick; one to which the characters and their tribe are immune, as would a handful of tribes across the globe.
Use your imaginations, build your own worlds and throw away every single book that has a sword, crossbow or the words "Enchanter," "Sorcerer," "Apprentice," "Assassin" or "Daughter" on the cover. And anything with a picture of some hooded individual out of a video game; consign the book to a fire, with prejudice. You'll learn nothing from these, only dry and dusty fourth-hand rehashes of other people's faded dreams.