B1 "In Search of the Unknown" has inspired multiple homages and conversions to related game systems. These provide a wealth of ideas for DMs running the classic module, or can be run on their own.
The mystery surrounding the disappearance of the two legendary inhabitants of the Caverns of Quasqueton has also resulted in two notable sequels to the original adventure, covered in greater depth, tomorrow.
B1 Quest for the Unknown:
Cover to B1 "Quest for the Unknown" (2002) by Brian Jelke, Steve Johansson, and David S. Kenzer. Illustration by Stacy Drum.
While including an element of parody, the adventure is filled with several interesting twists and ideas based on the source material, (the spiral, dead-end corridor leads to the ruins of the lookout tower, for example, something I hadn't been aware of).
Although many sections are taken verbatim from the original module, the text is heavily paraphrased, and includes a fair amount of useful new material, (such as a whole page devoted to books that can be found in the library).
The Hidden Serpent:
Cover to "The Hidden Serpent" (2010) by Jeff "Bighara" Sparks. Illustration by Joanna Barnum
Rogar and Zeglin are a pair of mercenary warlords. Their underground fortress is named "Quazkyton", which is Draconic for "hidden serpent" in reference to their swift attacks from a hidden base of operations.
A rough map is included as a player handout, along with a few wilderness encounters before access to the stronghold can be gained. Although inspired by the Caverns of Quasqueton, the layout has been reorganized.
Multiple factions and subplots are provided, which make for a dynamic and action-filled scenario. "The Hidden Serpent" is a hidden gem, and can be plunked into any campaign with a minimum of changes.
Cover to DW1 "Lair of the Unknown" (2013) by Johnstone Metzger.
Fearsome Forbus and the Unknown Wizard "two of the greatest dungeon raiders that ever lived" were slain by the evil wizard Zamzomarr while constructing their subterranean fortress of Xallevyrx, deep within the Haunted Forest.
Metzger has devised an evocative setting for his dungeon delve. A 17-page preview of the 110-page book is downloadable here.
Cover to "Zelligar's Evil" (2016) by Alzarian Crimson.
"Zelligar's Evil" was originally developed for use with Fantasy Grounds and comes with digital maps as well as player handouts, including books from Zelligar's library.
Cover to "Into the Borderlands" (2018). Illustration by Jim Roslof, from module B2 "The Keep on the Borderlands"