In Pendragon, the Gamemaster is the leader of the game, the source of knowledge, the organizer of society, armies, and the land itself. Without the Gamemaster there would be no game; in roleplaying there is not a more noble act than to take on this great responsibility.
The Pendragon Gamemasters Handbook is full of setting information about the world of King Arthur, Gamemaster procedures, and ideas to help the campaign flow smoothly.
Dolmenwood Official Adventure Scenario: Emelda's Song + complimentary PDF
Dungeon Crawl Classics: Dying Earth #9: Time Tempests at the Nameless Rose
Root: The Roleplaying Game - Ruins & Expeditions: Clearing Booklet 3