World-wise, there's multiple sapient species, and very few of them are "humans but [x]." They have different sizes, abilities, life spans and none of them are cultural monoliths. It really annoys me when I read a story and dwarves are just humans but short and they like to mine and also have Scottish accents, and all dwarves are like that, and they all live in those mountains over there, and they only hang out with other dwarves, and they hate all the other species because ????. That's not how reality works, members of a species will have different beliefs, live in different places, may have no cultural connection to their "homeland", but they'll still be different because of their bodies. A dragon is still going to grow really, really big and a human will never be able to fly (or see colors outside of the "visible" light spectrum), so any multi-species settlement will have to be designed to take these into account. Or, more likely, prioritize one species over another. Early on you see a bird city where there's these beautiful tall stone buildings and these well-designed aerial pathways....and on the ground is total chaos, houses and shops and carts and stuff being stuck wherever there's space, even if it's on top/in front of another building already there. The bird buildings are like gothic cathedrals, the human buildings are like cave swallow colonies.
In my other fantasy project, there's no magic, no one even uses that word, it's all alchemy. A unicorn's horn CAN neutralize any poison, but that's because there's some natural compound that is within the ivory that does that (like how silver and honey is naturally antibiotic). All the "magic" is handled in a Very Serious scientific or (materials science) engineering format. But the Noble Metals are special/inherently different than the other metals, the 3 constituent parts of the atom are sulfur/salt/quicksilver, the other "planets" are actually perfect crystal spheres...so (real world) alchemy is 100% correct, which does mean I can do some things that break the laws of our current understanding of science, but fits perfectly well with what we used to believe was true.
I love biology, chemistry, and physics, so a lot of my world/magic building is based around those. I've always been fascinated by our ever-changing models of the natural world, how they were all essentially true, for the world that we could observe at the time, and we had no way of knowing what they would look like in the future. I recently read Last and First Men, which is an early speculative biology book written in the 1930s. It correctly predicted WW2 and America being the dominant world culture, along with Mars once being wetter and habitable to life and genetic engineering....but it took humans something like 200 million years to finally figure out how to go to space. Everything about space travel in it is incredibly incorrect, but how could the author know? The 1930s wasn't all that long ago and so much has changed in such a small amount of time, there's a wealth of inspiration looking at visions of the future based on past scientific understanding.