Well, to start off, I'm a gamemaster who runs homebrew adventures in a homebrew world in a homebrew game system, so while I'm certainly familiar with Dungeons and Dragons, I don't personally play it. (I found its reliance on magic and character classes to be a little too limiting for the types of stories I wanted to tell, and, rather than try another system like any sane person would, I decided to patch together my own.) However, when I saw this bestiary at my local library, I had to give it a read.
While this volume still has the familiar fantasy standbys (drakes obviously, as well as a spattering of forehead-alien humanoids), there are a number of less familiar threats. My personal favorites are the Zombie Cactus and Hunter Cactus, with the Floating Mantle, Mekillot, and Cloud Ray coming in a close tie for second. I can easily see myself using a lot of these creatures in desert settings across a large variety of games. In particular, I think they would be useful for post-apocalyptic campaigns (which is technically what the Dark Sun campaign setting is in a fantasy rather sci-fi sense) as well traditional fantasy or pulp adventures.
Personally, I would have preferred fewer humanoids or at least more non-humanoids, but that seems to be the nature of most bestiaries.
3.5 stars