I have Giants, Monsters & Dragons by Carol Rose. It's a global reference book but includes North America.
Giants, Monsters, and Dragons one of my go-to reference books. Has just about every creature in there except for a few very niche ones that only I'd know about because I'm a mythology nerd.
I would reccomend picking up this book. It's got a very, very broad cross-cultural selection, and then in the back it has appendices where you can cross reference creature by culture of origin, type, (giants, dragons, etc), theme (associated with mountains, associated with water, etc) and so on.
Excellent reference material, though some entries are more detailed than others. It's best for giving you an idea of things you might want to investigate more in depth.
I mean, Element Encyclopedia has books on everything for that. Not my particular favorite brand (mostly because I am a huge mythology nerd and have better books on monsters) but their selection should work for you.
But my two personal recomendations for any fantasy are
and
Just buy this book and read it: https://www.amazon.com/Giants-Monsters-Dragons-Encyclopedia-Folklore/dp/0393322114