A nomad protagonist whose primary character arc involves coming to terms with having to travel everywhere and never having a place to call home.
In a gladiator match, a bird flies around and annoys the gladiators by pooping on their heads during dramatic moments.
An executioner has a deep, heart-to-heart talk with the person s/he’s supposed to kill — on the gallows, in front of the crowd.
Your protagonist has time-altering powers, with one big catch: s/he can only use them when s/he’s late and needs to be on time.
A level-based shape-shifting system: shifters start being able to change their eye color, then hair color, then skin color, then facial structure, and finally, body structure after around 20 years of training.
A magic system like large-scale sculpting; mages can add, remove, and edit landmasses to create continents, islands, and oceans.
A magic system that doesn’t let people die till their dreams come true.
A magic system that allows visual alteration of reality, but nothing else. You could change a horse into a cat and it’d still sound like a horse. The only difference would be that its rider would appear to be hovering five feet above a cat.
Magic is based on food. What you eat determines what power you get till your next meal.
Put a powerful character in a situation in which s/he feels completely powerless — without introducing a more powerful villain.