The cover to module B2 "The Keep on the Borderlands" depicts a party of adventurers battling a group of hobgoblins, with the Caves of Chaos visible in the background (see this thread at Zenopus Archives for additional discussion):
Cover to original version of module B2 "The Keep on the Borderlands" (1st printing, 1980). Illustration by Jim Roslof, the original color study for which sold at auction for over $10,000 in 2017.
The distinctive purple border and cover illustration of the original version were re-used for Goodman Games' OAR #1 "Into the Borderlands" (2018).
Cover to French version of module B2 "The Keep on the Borderlands" (1st printing, 1982). Illustration by Jim Holloway.
Holloway also provided a new frontispiece for the module, depicting a group of adventurers fighting the owlbear from Cave G.
As with module B1, there was a Dutch version of "The Keep on the Borderlands" using art by Jeff Easley for its cover:
Cover to Dutch version of module B2 "The Keep on the Borderlands" (1988). Illustration by Jeff Easley.
Easley's illustration could be depicting the ogre from Cave E, although was originally used for the cover to the Apple IIe "Dungeon!" computer game:
Apple IIe "Dungeon!" computer adventure game (1982). Illustration by Jeff Easley.
The Apple IIe "Dungeon!" game was released in 1982, the same year Easley began working at TSR (see this review in Electronic Games vol. 2, no. 7 (September, 1983), which includes a reproduction of Easley's cover art).