Some interesting things:
Flinds have abandoned their flindbars, which were honestly always kind of goofy, for new Yeenoghu-blessed triple-headed flails, which further cements Yeenoghu as "god of the gnolls".
The Pit Master artwork previewed by WoTC now officially confirmed as being a new Yuan-ti strain (check out the notes from Volo & Elminster on the Yuan-ti Nightmare Speaker excerpt).
Shoosuvas, demonic ghoul-hyenas, return after having descended into obscurity.
Lizardfolk apparently tend to feel protective towards "soft ones", which suggests that they may be one of the PC races we're getting in this book.