If there's a race of non-human, non-monster sapient beings in your fiction, you're most likely looking at either Sci Fi
. Further, the race probably has characteristics drawn from a common set of tropes. These are some of those tropes.
Writing an entirely different race is hard. There's a lot of detail to manage, and to communicate to the reader. Some writers go to extreme lengths in inventive originality — this tends to become the focus of the work, whether intentionally or otherwise. Strategies adopted by writers for dealing with these difficulties include drawing the race more or less directly from some stock template with which the audience will be familiar, going to the Planet of Hats
, or, at the furthest extreme, just giving up on the "fantastic" part of this trope altogether. Original Star Trek
Klingons, supposedly an "alien race", famously look and act almost perfectly human.
Races defined by their sheer unintelligent monstrosity
generally don't fall under this set of tropes. Mythical creatures are covered by Our Monsters Are Different
: I wonder why they keep mentioning life on other planets. Waldorf
: Why should they care? They don't have lives on this one! Both