Um, I went with the standard fantasy races because my plot demanded that I have a “generic fantasy world”.
I really like dwarves and halflings, so when I was making my fantasy world, I thought it would be funny if everyone in it was short, and make most other living things (trees, animals) gigantic, then build a world around it. So I added in gnomes and goblins. I usually hate elves, but I eventually put them in and made them short (you know, like those Christmas elves).
I have other races I’ll lump into “fairy folk”, but I don’t really touch on them very much, except for this one treant named Morgan Treeman. I mostly just wanted to add them in because of the above reason, and they’re there if I ever need them. I was also playing with the idea of adding in orcs and exploring their point of view, but I haven’t found a way to introduce them yet.
Technically, the five races I have were pretty much all humans, but they were punished by their gods and made them all really short and separated them from each other. But before I go off on a worldbuilding rant…
I’d say go with what you want to see. If creating new races is too much of an effort, then change the other ones to your liking, and as your story needs it, as long as you don’t make them a one-dimensional race (you’ve seen one, you’ve seen all of them), but you probably know that already.
Mine aren’t supposed to have a long screen time (because of my premise and story structure), but I ended up developing their culture anyway (mostly the dwarves and halflings) because it was very fun playing around with the tropes. They were also a nice contrast to my (human) children MCs who are from another world, since they suddenly meet all these people almost the same height as them but are actually much much older. They even mistook some of them as couples.
Also, just imagine dwarves and halflings riding griffins, dragons, elephants, raptors and ornithopters. It’s just not the same with a “taller” race, you know?