I am posting this as a further thank-you, someone pointed me to a site where someone had posted PDF scans of many Dungeon issues and from those I've extracted a partial list of Underdark Scenarios, starting with what seems to be the first back in issue 20. I've always been interested in this part of the D&D universe ever since I saw Issue 70 of Dungeon, with Kingdom of the Ghouls.
Dungeon Magazine, Underdark Scenarios.
Ship of Night, Wolfgang Baur, Issue 20, pg 6-25
Thunder Under Needlespire, James Jacobs, Issue 24, pg 38-60
Shards of the Day, Randy Maxwell, Issue 60, pg 8-30
Swing Shot, Chris Doyle, Issue 66, pg 36-37
Uzaglu of the Underdark, Christopher Perkins, Issue 67, pg 70-74
Kingdom of the Ghouls, Wolfgang Baur, Issue 70, pg 48-78
The Amulet and the Underdark, William Kenower, Issue 75, pg 26-42
I'll update this list as I go through the issues.