From publisher blurb:
Welcome to the Retroverse!
An exciting new 5E universe from Lasers & Liches that resides in a place of half faded memories, barely remembered songs, lost childhood friends, outdated styles, abandoned dreams, lost playthings, vapor ware, and time corroded nostalgia. A place both strange and familiar. A place for adventure, friendship, chaos, and the magic of yesteryear. In short, a place that combines your love of the present with your adoration of the past.
The Game Master's Beats features over 120 new creature stat blocks, over 100 new magical items, a huge world map with rules on how to make your own, a d100 adventure generation table, a full adventure taking players from level 1 to 18 or more, and a few other neon-tinged surprises!
Version 3 has had a complete overhaul of every stat block in previous versions, updating them for clairty and bugs. There are several additions to monsters, world locations, and magical items. The larget update is the final addition to Warren's Grove: the Black Castle. It is a mega dungeon of over 120 rooms, full of secrets, goofs, and enough adventure to keep your players busy for months! This version of the GMB is nearly finalized, with onlky some additional backer content missing.