Aaaah, I love designing the natural environments for my worlds! My first one was a high fantasy, and most of my inspiration honestly came from African flora and fauna as well as various mythologies (for instance, there's gryphons as just a predator endemic to that world), in addition to my local habitat which is generally pretty temperate. I'm also a severe bird nerd, so I must admit that a lot of my newfangled animals possess a lot of avian traits. As I recall, I just...sat down and started making it. I started with what biomes I wanted in certain areas of my world, then added animal life, and from there, it took off! The more I built, the easier it became to add more, and soon enough, there was a whole new world.
In a more recent world (a version of Hell), I started with the people and history, then started making the climate. I wanted it to be barren and harsh, with some aspects of a more typical Hell (like volcanic activity) but also wanted variance. After all, Hell is an entire world: it needs to have different biomes and creatures. The short version of what I came up with is a somewhat earth-like realm that's a kind of medieval-ish dystopia, having survived several apocalypses, since I didn't want to entirely lose the roughness of Hell. Most of the flora and fauna had died out but there are still different ecosystems: there's forestlands, deserts, plains, and mountains, each with different beasties and all. This shaped both the natural lands and the culture. I think that, for this world, I drew a lot of inspiration out of areas like the Gobi Desert and the Mongolian steppes: wide, open, dominated by shrubby vegetation that, although life-supporting, is a difficult area to scrape a life out in.
