The Game Master's Book of Traps, Puzzles and Dungeons

The Game Master's Book of Traps, Puzzles and Dungeons: A punishing collection of bone-crunching contraptions, brain-teasing riddles and ... RPG adventures (The Game Master Series)

The Game Master's Book of Random Encounters: 500+ customizable maps, tables and story hooks to create 5th edition adventures on demand (The Game Master Series)

The Game Master's Book of Astonishing Random Tables: 300+ Unique Roll Tables to Enhance Your Worldbuilding, Storytelling, Locations, Magic and More ... RPG Adventures (The Game Master Series)