old-school-rules version of Quests of Doom, a book of 18 adventures. The authors are definitely old-schoolers, although there's a slant into authors of the late 1e and early 2e era more than the classic 1e or earlier. However, the rule set is Swords & Wizardry (0E) (click format to pdf for free copy of rules), and the mission statement is to produce adventures that fit the 0E/1E mold (avoiding railroading, too-strong NPCs, etc.), and there are strong authors with non-2e chops (me, Bill Webb, Casey Christofferson, and Michael Curtis, to name 4)
The list of authors is: Matt Finch (Swords & Wizardry, Tome of Adventure Design), Ed Greenwood (The Forgotten Realms Campaign Setting, The City of Splendors), J. Collura (Caverns of Thracia Reloaded, Chaos Rising), Michael Curtis (The Dungeon Alphabet, Realms of Crawling Chaos), and Casey Christofferson (The Tome of Horrors, City of Brass). Throw in a few D&D long-timers like Steve Winter (Tyranny of Dragons, Murder in Baldur’s Gate), James M. Ward (Gamma World, Pool of Radiance, Castle Keeper’s Guide), Skip Williams (Axe of the Dwarvish Lords, The Rod of Seven Parts), and Bill Webb (Rappan Athuk, The Lost City of Barakus).