Savage Encounter is giving away their unoffical D&D supplement, Villains & Lairs III, as a "pay what you want" downlaod on Dungeon Masters Guild.
Expand your game with this collection of 8 NPCs of various challenge ratings, one of which includes and map and details of its lair. Add these NPCs as a side-quest, a main villain, a one-shot, a bounty for easy money, or however else you wish.
Each NPC includes an image, a backstory, motives, flaws, and a stat block. Some even include new magic items!