I love making my worlds as unique as possible, high fantasy lends well to that.
A magical world where the main character's home has been conquered by another leading to her plans. Interesting fact: the main character is the bad guy
A futuristic Earth that was destroyed by climate change leading to impossible to survive environments, people had to adapt and mutated to survive. Lots of made up tech, mutated humans and lots of science.
A fantasy world where two kingdoms are fighting a war that they forgot what caused it, two princes decide to change that.
A magical world where a war of the gods and goddesses caused all of the land masses in the world to be lifted into the ground where they are permanently suspended, leaving the surface nothing, but sea. But the people didn't care that all of their land is floating in the air, they made it work.