Mentioned in the 'Kobold Press 5e material' thread, but really worth its own thread ... :)
The Tome of Beasts brings more than 300 new monsters to your 5e game—everything from tiny drakes and peculiar spiders to ancient dragons, arch-devils, and demon lords. The Tome of Beasts covers a huge gamut of challenges, from basic vermin to world-shaking personification of malevolence, and everything in between!
In addition to the MASSIVE, richly-illustrated, full color, hard cover Tome of Beasts, there is also a companion book, the Book of Lairs, which presents short, detailed lairs, including an Alchemist's Guildhall, Bloodstone Grove, the Umbral Tower, and the Lost Halls of Everforge. Each lair spotlights a monster from the Tome of Beasts and comes with a 24" by 36" battle map is for use in virtual table tops, projectors, or printing out full-color and ready for play!