Adventure Calls. This supplement for Four Against Darkness adds plenty of optional rules:
Guidelines for Troupe play
Rules for stealth, streetwise, banking, magic lockers, gambling and hidden treasure troves
New equipment and spells
New monster tables (riff-raff, ambushers, weird monsters, chaos cultists)
Rumors, Scenes and Red Herrings
Nine new thematic dungeons
Rules for joining an Adventurers Guild
Tables for Guild Jobs and unique minor quests
Rules allowing you to play with 1 to 3 characters
Trinkets – six new minor magic items
A ready-to-Run hex-crawl campaign
This book requires only Four Against Darkness but also provides many interactions with other titles.
D6, d10 and d12 are required to play.