An Adventure for Character Levels 5 - 8
This fan-created dungeon does not explicitly enumerate a rules set compatibility, but most of the statistics blocks are styled for "D&D".
From the introduction:
In mythical Osasia, elves have never been known to have burrowed underground tombs, yet the contents within this structure are undoubtedly elven. Who or what created the Tomb of Osgameria, and what waits within?