Gaming

Chaosium Inc

Call of Cthulhu: Malleus Monstrorum: Cthulhu Mythos Bestiary

Konosuba: God's Blessing on This Wonderful World! TRPG

Paizo

Pathfinder Adventure Path: Abomination Vaults (P2)

Paizo

Pathfinder RPG Rage of Elements (P2)

Wizards of the Coast

Underdark (Dungeons & Dragons d20 Fantasy Roleplaying, Forgotten Realms Accessory)

Paizo

Pathfinder RPG: Pathfinder Player Core (P2)

The Game Masters Handbook of Proactive Roleplaying: Guidelines and strategies for running PC-driven narratives in 5E adventures (The Game Master Series)

The Game Masters Book of Villains, Minions and Their Tactics: Epic new antagonists for your PCs, plus new minions, fighting tactics, and guidelines ... RPG adventures (The Game Master Series)

So You Want To Be A Game Master: Everything You Need to Start Your Tabletop Adventure for Dungeons and Dragons, Pathfinder, and Other Systems

White Box: Fantastic Medieval Adventure Game

Return of the Lazy Dungeon Master

Wizards of the Coast

Tomb of Annihilation (Dungeons & Dragons)