I'm curious what sorts of inspirational things you might know about from the real world you pull into game, especially if the things are not something we're likely to encounter in our everyday lives and/or the game world is not a modern setting. These things can become monsters, organizations, places, etc.
For example, I'm fascinated by things from the deep sea that may seem terrifying, such as this hydrothermal worm under an electron microscope, which could serve as a great visual for a monster.
image from FEI
Or this place in Turkmenistan known as the Door or Gate to Hell, a 230' across x 65' deep crater that opened during an oil drilling accident and lit the natural gases on fire--fires that have been burning for more than 40 years.
image from the Smithsonian