Module B1 "In Search of the Unknown" was intentionally vague about the fates of Rogahn the Fearless and Zelligar the Unknown, leaving open the possibilities for further adventures. There have been two notable sequels, one co-authored by Mike Carr, himself.
B0.5 Secrets of the Unknown:
Cover to B0.5 "Secrets of the Unknown" (2015) by Bill Barsh. Illustration by Matt Costanzo.
B1 Legacy of the Unknown:
Cover to B1 "Legacy of the Unknown" (2011) by Bill Barsh. Illustration by Chris Letzelter.
Cover to LR6 "Discovery of the Unknown" by Michael Carr and Paul J. Stormberg. Illustration by Darlene.