Tolkien's mythology is full of strange creatures beyond count, and here are some of the more interesting ones.  For some more detail on some of these topics, see these other videos:   

"Deleted Scene": Tom Bombadil: https://www.youtube.com/watch?v=IKfG0vP_INs  

Middle Earth Mysteries (including more on Bombadil): https://www.youtube.com/watch?v=VE3a9hiEKY8  

Creatures of Middle Earth: Elves: https://www.youtube.com/watch?v=tiBiNWAtsXo   

Creation of Arda: https://www.youtube.com/watch?v=Je67LfK98vg   

And here's the book I referenced: https://www.amazon.com/Guide-Tolkiens-World-David-Day/dp/1571458786/ref=sr_1_3?ie=UTF8&qid=1516582137&sr=8-3&keywords=guide+to+tolkien%27s+world  

Intro and outro music from "Many Meetings," LOTR Trilogy Soundtrack, copyright New Line Productions and Reprise Records.