So what would they look like to you? How would you distinguish them from humans or the 20-odd other humanoids?
Firstly, I wouldn't include that many if the goal was to create really distinctly different groups. I'd go for (at most) 6-ish, because coming up with even five such distinct things would be a challenge. If I were sitting down and spending the years necessary to pre-write a fantasy series, I'd do substantially more work and could possibly push things up to the 10-12 range, but I wouldn't expect that of just anybody.
Though realistically my preferred solution is a mix--yes, certain races are mostly similar to humans, and those races tend to be the ones that get along swimmingly and form mixed-racial communities, which is a classic fantasy trope all its own. But there can also be more "alien" races that require caution to understand and work with, because their physiological needs and their ingrained values
differ from the humanoid races.
A key example here is JK Rowling's goblins. Both humans and goblins have beefs with one another, but we get to see a fascinating look into how goblins differ from humans through Bill Weasley, who works with them as a curse-breaker for Gringotts. He teaches Harry that "property" and "theft" and "sale" to a goblin don't mean the same things they mean to the English, and indeed to most human cultures with such concepts. To the vast majority of human cultures with a concept of "property" (which is most of them), property belongs either to some specific person, or to a collection of people (and no, those stories about how Native American cultures had no concept of "property" are not really true--they saw property as group-centered or leadership-centered, rather than purely individual-centered), and the transfer of property, unless otherwise specified, is a permanent exchange.
Goblins do not see it that way; to a goblin, if you create something, that means it belongs to you
forever, it is bound to you and you alone because you are its creator. You can "sell" it to someone else, or create something on commission for someone else, but it is and always will be yours; the buyer or commissioner is simply
borrowing it from you for a specified period of time (often the purchaser's lifetime). To the goblins, a human passing down a goblin-wrought sword to her daughter is "stealing," permanently taking the fruits of that goblin's labor. To the humans who purchased that sword, the goblins coming to take it back are "stealing" it. This has led to centuries of bad blood and strife between the two species, and both sides resent the other pretty strongly.
Now, I'm not going to defend Rowling's use of some questionable stuff about goblins generally (they're not exactly subtle in which
particular ethnic groups they reference...), nor her other attitudes about unrelated issues. But this is a neat, simple, easily-explained example of how you can articulate a genuinely different
fundamental value compared to
pretty much all humans. (I don't doubt that there's a possibility that a human culture exists or has existed which had an idea of property and exchange like HP goblins', but I've never heard of it and it's never come up in a discussion thereof, so I'm reasonably confident in calling it "unusual" among humans at the very least.) And this is a fundamental value difference that isn't even derived from thinking about the species' physiology or implicit connections to other species (e.g. dragonborn and dragons, elves and faeries, dwarves and their wars with giants, etc.), which can lead to all sorts of ideas as noted above.
