What about humans is unique to our species and what's just a function of our intelligence?
So, this is a general sci-fi kind of question really. One that is hard to answer solidly, because we only have the one example of technologically advanced species to go on.
I note that D&D is a fantasy game. It isn't really there to ask the speculative question, "What if...?" Heck, in D&D, even the concept of "species" is a bit weakened by having so many things able to interbreed. And in D&D, what species you have are not necessarily results of evolution, but are instead created by gods, and there are gods guiding our interactions with, and development of, technology.
D&D might be better positioned to look at the questions of the influence of higher powers, than the limits of biology.
What would other intelligent humanoids not share with us? Compared to other animals on Earth, physically we have high endurance, we sweat, and we can throw things. But what functions of our intelligence could be unique and not shared by other intelligent lineages?
Why limit yourself to functions of intelligence?
Author Alan Dean Foster (in "The Damned Trilogy") turned the "humans are the generic" trope on its head, by envisioning a galaxy in which there were other intelligent alien races... but
humans were the ones who appeared to be hyper-specialized for fighting. Every other species was more technologically advanced than humans, but also softer, squishier, and more psychologically disinclined to violence than humans. So, like, even an accountant who goes to the gym a couple times a week looked like Conan the Barbarian to the aliens.
Would all intelligent humanoid species end up with the same technologies, or are some things uniquely human? What if the propensity to personify animals was uniquely human, and thus animal domestication was uniquely human? Or are D&D humanoid species just too similar to end up drastically different?
I was watching an episode of The Muppet Show last night, and was struck by the realization that birds (indeed, no creature without human-like lips) can play the trumpet, or really any of the wind instruments humans have invented. And thus how art is inexorably linked to biology.
Animal domestication isn't really a function of our propensity to personify animals - it is mostly a function of not wanting to have to run after cows and pigs and goats to be able to eat them, and the propensity for a few animals to not mind being told where to go quite so much.