Solo and Lone Hero D&D Adventures? A party of one...

I woke up this morning wondering if there were many solo D&D adventures. I'm talking about one-on-one or head-to-head style one player and the DM type adventures. Turns out there were, though finding them wasn't the easiest. There are also apparently a number of solo-as-in-D&D-solitaire adventures: I suspect the first 7-ish on the list are really D&D solitaire, and the others are head-to-head, one-on-one, or lone-hero ones. But here's the list I've found:

Actual solo/solitaire D&D modules:

• Ghost of Lion Castle (BSOLO)
• Mystery of the Snow Pearls (CM5, red viewer)*
• Blizzard Pass (MSOL1, invisible ink)*
• Maze of the Riddling Minotaur (MSOL2, Invisible Ink)*
• Midnight on Dagger Alley (MV1, red viewer)*
• Lathan's Gold (XSOLO)
• Thunderdelve Mountain (XS2)

One player + DM modules:

• The Gem and the Staff (O1, Thief 8)
• Blade of Vengeance (O2, Elf 7)
• Eye of the Serpent (UK5, Ranger/Druid/Monk + 3NPCs)
• Fighter's Challenge (HHQ1)
• Wizard's Challenge (HHQ2)
• Thief's Challenge (HHQ3)
• Cleric's Challenge (HHQ4)
• Fighter's Challenge II (HHQ5)
• Wizard's Challenge II (HHQ6)
• Thief's Challenge II: Beacon Point (HHQ7)
• Cleric's Challenge II (HHQ8)

The ones marked with an asterisk look like bad options: they use either a gimmicky red plasic "magic viewer" or an invisible-ink revealing marker, and also aren't on dndclassics.com. Not all the others are on D&D Classics either: the modules in italics do seem to be available in pdf format though. So not all of these are really out there as options, but maybe the BSOLO and XSOLOs will show up eventually, though I suspect these are really solitaire adventures (Cover images are easy to find online, but not the back cover or first page where you'd find this info). The gimmicky ones might be harder to track down and/or missing the vital gimmicky component on the second hand market. Obvious potential problems if things are already revealed or marked up or just plain inaccessible.

Some of these predictably use a pre-generated character (not uncommon for older D&D modules, especially coming from tournament play), or a small set of classes (e.g. Wizard's Challenge, etc.). 

Given the HHQ series in AD&D 2nd Edition, there's actually a reasonable looking array of these adventures on paper. Unfortunately, the reviews of these things are sparse and nonexistent, and most people who are even proficient reviewers for old school modules might not have much experience with solo adventures.

As far as I can tell this is a comprehensive list of published TSR adventures. Since the wikipedia List of Dungeons and Dragons Modules doesn't go past the year 2000, there may be 3rd or 4th edition stuff. I know there was one truly solo 4e adventure in the D&D Insider nonsense: as in one player without a DM. The 4e Red Box apparently had a couple "solo" adventures which seem to be to get the DM to learn the rules, and there's a Dragon magazine followup solo adventure to those ones. But there could be some later edition stuff or Dungeon adventures that I missed.

Expeditious Retreat Press published a number of 3.5/Pathfinder one-on-one adventures. It looks like the compendium updated the 3.5 adventures to Pathfinder, and they seem like the next reasonable place to look for one-PC D&D.

Also, there may be some modules/adventures like Beyond the Crystal Cave which have very little emphasis on combat: this type of module could essentially be a solo module too, but I'd have to look into it in detail.

[Update: a bit more info in part 2. Also check out the comments below.]