From Chris Lindsay on Twitter: "I fought hard to bring these bad-frogs back. SO... YOUR WELCOME!!!"
New issue of Dragon+ has a Volos Guide preview. Hags have their own section in Chapter One after all, so there are eight sections with seven maps. Based on the latest podcast description of the Gnoll, I suppose they lack a map.
Have the stats for the Annis Hag on page 159 from Chapter Three, and the Slithering Tracker, a medium ooze with 1E roots on page 190.
So I came across this article on Polygon
http://www.polygon.com/2016/10/28/13460414/volos-guide-to-monsters-giveaway
Being unfamiliar with Roll20, when it says "over 130 statted tokens", does that mean there will be over 130 monster stat blocks (so that the 96 monsters we'll be seeing will have 130+ stat blocks after variants) or can "statted tokens" also include the information on playable races as well?

Like the player races, some of the monsters have been leaked:
View attachment 78037
So, from what we haven't seen already previewed, I'm very happy to see the babau (so the book isn't shying away from the main extraplanar races like demons), the bodak, the brontosaurus (YES! More dinosaurs! The lack of a typical sauropod from the MM was very noticeable, and hopefully we'll see a smaller predictor like deinonychus and/or velociraptor and a stegosaur at the least as well), and the catoblepas (which I had very much wanted to see updated). With what has already been previewed, and now knowing that we'll be seeing additional demons, dinosaurs, and the catoblepas, I can only hope we get gibberlings and quicklings in the book, and I'll be very near 100% satisfied with the updates!
It looks like this is in strict alphabetical order, and not in the order they will appear in the book, since we know the hags and the alhoon will be under "H" and "M" respectively in the actual book. I assume all the NPC-types will be in their own appendix (and there looks to be an interesting assortment of them, even in the first few letters of the alphabet). Those "Booyahg" types are goblin variants alluded to on the preview page we've seen already...

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.