The Lost Crypt (5E)

From publisher blurb: Written by veteran RPG scholar and scribe Bill Silvey, The Lost Crypt is an old-school style romp through an ancient tomb and hidden lairs filled with clever monsters. This is the Bill-created portion of a joint project with Gary Gygax, designed to be a challenge for veteran characters of 7-8th level. A realm not terribly unlike our own exists in a strange and mostly-hospitable nearby plane of existence. While planar travel might overlook this small pocket of reality, an entrance into it exists at the deepest depths of the most storied dungeon complex in the known world. To enter this planar region is to step into a world at once familiar and yet more bizarre than our own. Herein there are rumored to lie artifacts of great power, and treasure beyond imagination. Having explored the uttermost depths of the dungeon and found the entrance, a group of adventurers can make their way beyond the boundaries of reality itself in search of fame and fortune!