Magic that causes people to snap in and out of the dimension they currently occupy, essentially giving them video game-like lag in real life.
The weapon of the gods, the most powerful artifact in the world, is a folding chair.
The protagonist is the biggest jerk in the world, guilty of no crimes, but just generally an unpleasant person to be around. The antagonist is literally a saint.
A world in which technology has surpassed magic. Magic is then used only to augment technological progress. Powerful wizards get smartphones, etc.
A mineral harder than diamond that scientists on your world use to construct vessels capable of exploring the deepest parts of the ocean. With space travel not pertinent, have your protagonist explore the deepest parts of the planet.
Write a sentient species that pops open like popcorn when heated and becomes an entirely different sentient species after popping.
A species like humans, but where women have male genitalia and men have female genitalia — while all other sex-specific anatomy remains the same (that is, the differences in rib structure, build of pelvis, general height, etc.).
When your hero retires from adventuring, s/he writes a book about it. In the book, s/he lies about everything because s/he feels the real events were too interesting.
A world where storks actually do drop genetically accurate babies off at people’s front doors, and sex is just a thing that exists with no real outcome.
When a disastrous new villain steps up and writes new laws, artists’ original ideas can legally be stolen and the artists can be fined, so long as they’ve used at least one of the same words in their book’s title as another author, or the same color as another painter in any of their paintings.
(This is a prompt for a comedic scenario, but wanna know something sad? This is actually happening right now.)