This is a 3.0 book, but hey, monster templates are easy to convert to 3.5. I'm not sure I'd want the job of converting all the templates, considering how many there are. Loads of value in this book, folks.
If you enjoy tinkering with monsters, this book is for you. And by that, I mean, "What are you waiting for, buy it this minute, you have no idea what you're missing."
A Heightened (+2 to all attributes and some other stuff) Half-Medusa (stoning gaze) Nymph who is an Argent Servitor (servant of good)
A Woundmender (construct with fast healing) Skinrug (self-explanatory) made from the pelt of a Displacer Beast
A (well, not for long) Hypermitiotic (divides when struck) Hiveling (gets bonuses when around other creatures of its hive).... anything. How about stirges or kobolds?
Apocalyptic Tarrasque? Half-efreeti Centaur? The possibilities are about as endless as they come.