Would you rather a lizard man or a sleestak?
A good campaign subverts the players expectations. We've all internalized the idea that you say "The bony forms of three bodies infused with unholy power rise up and move towards you," instead of "you see three skeletons".
That's trivial. If that's all you're doing, then players are only engaged till they find out whatever special powers you've given the current monster. How are these skeletons different?
This blog is about how to use things directly in play that support agency and improve your game without resorting to numbers. How to apply that to monsters?
Now, taking the naturalistic route is kind of trivial (THANK YOU DRAGON MAGAZINE. I TOTALLY NEEDED TO KNOW NYMPHS DON'T LIKE IT WHEN THEIR HAIR GETS CUT). I don't really believe that's very helpful.
What's important for your campaign is that monsters are exotic. That you know who and what they are. A selection of a few interesting monsters can provide grist for years, over flipping through a book, looking for the next deadly thing. Some companies understand this! (A professional example from a company that understands this).
So this exercise should help.
Do you want to thank me? Use one of the variations in your campaign and come back to comment and tell me how it went!