I have Return to the Tomb of Horrors and Red Steel. RttToH was cool in several ways: it included a reprint of the original, it incorporated the original, the expanded material was cool, it was deadly, and it had "this is what you see" art. Red Steel wasn't cool at all; it sucked.
I have exactly the opposite opinion of the two. Though the Savage Coast setting got even better with the online release, IMO.
Here's my list while I'm at it.
Mystara
Glantri, Kingdom of Magic
Karameikos, Kingdom of Adventure
I was deeply disappointed with these two boxed sets. Mystaraphiles could go on about why these bcame such a disaster, but the fact they were 95+% reprinted material from the Gazetteers were likely reasons for the line's failure.
Red Steel
Savage Baronies
The Savage Coast setting matches Al Qadim for its wonderful use of AD&D Kits. The execution of the kits demonstrates how well kits could work for AD&D. The Red Steel campaign was a substantive advancement from earlier material available on the Savage Coast, plus, the whole Red Curse was altered for the boxed set to remove any possible association with drug addiction that earlier version of the curse seemed to hint at. It was also made far more complicated. Plus, the audio CDs the came with these boxes were actually useful for ambient adventure music!
Hollow World
Hollow World's greatest feature is that it included entire planet maps of the outer surface, the entire inner surface, plus a map of the planet prior to the Blackmoor cateclysm.
Mark of Amber
Night of the Vampire
Hail the Heroes
These there adventure boxed sets were very much "meh" to me. Never got into the whole audio CD component fad of TSRs.
Champions of Mystara
This was Bruce Heard's swan song and likely love letter to the Mystara fans. This was the last "Basic" D&D accessory before the AD&D conversion cluster ****. It includes rules for skyships, a selection of the Princess Ark stories, and gazetteers for the Sind and Graakhalia.
Twilight of the Emperors
Part of the acclaimed Gazetteer series, and the only boxed gazetteer. Covers to empires at war with each other, the warrior ruled Thyatis (kind of Roman/Byzantium) and the mage ruled Alphatia (a nation that came from across the stars to colonize the planet and came to dominate a huge area)
Wrath of the Immortals
Includes new rules for becoming immortal as well as an adventure that reshapes the entire world. Literally! Nations sinking beneath the sea, comets obliterating mountain ranges.
Basic (Menzter)
Basic (Holmes)
Expert
Companion
Master
Immortal
BECMI! Still, by far, my preferred cosmology for D&D is that presented in the Immortals boxed set.
Greyhawk
Wars
*cringe* Not sure what the point of this board game was. Yes, it really was a board game with nothing to do with AD&D, though it did advance the setting into . . .
From the Ashes
I love From the Ashes. My preferred era of Greyhawk.
The City of Greyhawk
When I bought this, at first, I was just happen to get something Greyhawk. But not long afterwards I began to feel regret, and then I resented the set. I felt like it was not the Greyhawk I expected it would be.
the original box
This set was my first campaign setting and my first box set. Fond memories still. It ignited my world building imagination that continues to this day. I still break it out for inspiration on how to say so much with so few words.
Spelljammer
Campaign Setting
The campaign setting was initially spotty, but the setting came into its own with accessories like Skulls and Crossbows, and the Complete Spacefarer.
Legend of the Spelljammer
I don't regret purchasing it, because I'm a completist, but knowing what really is in it I never would have bought it full price, I would have waited for a used copy.
Astromundi Cluster
I loved this, I just wished I could have DM'ed it. I break it out every now and then for inspiration at designing a Closed sphere.
War Captain's Companion
Helpful. I think it could have been better.
Dragonlance
Time of the Dragon
The only part of Dragonlance I care about. And I really love Taladas.
Forgotten Realms
Gray Box
Made me fall in love with the Realms. The maps inspired me more than any other maps I had seen yet.
Campaign Setting (2nd ed)
Began my falling out of love with the Realms.
City System
I love mapping, and the scope of the project this must have been was jaw dropping.
Ruins of Undermountain
I still dig this out for inspiration at how to design interesting encounters.
Ruins of Undermountain II
Fell flat in comparison to the first. I only use it for the box to hold all of my Undermountain products in.
Ruins of Myth Drannor
I loved the mini-dungeon encounter cards. I've reused many of them again and again. The rest of this set never got used and pretty much "didn't exist" in my campaign.
Ruins of Zhentil Keep
Fell flat. It felt like this was going to be ignored promptly and reinvented in a few years.
Menzoberranzan
Meh, I wanted so much more. I was not a drow fanboi, but I was an underdark fan. It didn't satisfy me. It will likely be eBayed someday soon.
City of Splendors
Even though it was so much more material than FR1, I can't explain why, but FR1 was a better product. I use FR1 over City of Splendors any day of the week.
Cities of Mystery
A waste.
The North
Better value for me than City of Splendors, but again, for me The Savage Frontier was more bang for the buck and I use it instead.
Elminster's Ecologies
Another on my list to eBay when I decide to. I had hoped it was going to be something more than it was. I like little parts, but the whole was not my liking. I think this was my final realization that post-Time of Troubles Realms was just not meant for me.
Netheril Empire of Magic
I don't know what I was hoping for, but it wasn't it. I grabbed it on impulse. Another to-be-eBayed item.
Lands of Intrigue
Empires of the Shining Sea
Two more products I think I like the FR softcover product over the boxed set. Tethyr was better fleshed out than before, which I liked, but not enough to make me care about someplace outside of the Heartlands and the North.
(I used to own Horde, and Maztica)
Planescape
Nothing anymore, I sold them all, yeah I owned all Planescape as well.
Al Qadim
Land of Fate Campaign Setting
City of Delight
Assassin Mountain
Cities of Bone
Ruined Kingdoms
Golden Voyages
Caravans
Secrets of the Lamp
A Dozen and One Adventures
The quality of the Al Qadim line has never been equaled again by any other line. I regret discovering it after the line was cancelled. As I said above, this setting demonstrated how one could make kits work.
Birthright
Campaign Setting
Cities of the Sun
Rjurik Highlands
Havens of the Great Bay
I loved Birthright as well. I enjoyed the different focus on the well worn themes of D&D settings. I never got into domain management, but I wish something like Birthright's rules could have been made more portable for other settings. I would love to try to make the BECMI domain rules and War Machine blend with Birthright and take them into Mystara.
Dark Sun
Original Campaign Setting
I love it. My campaigns all begin during this timeline.
Revised Campaign Setting
Meh. I love the changes and hate the changes equally. I can't explain it. I think its because I resent that the changes came about because of DMPCs rather than PC heroes.
City by the Silt Sea
Excellent adventure/sourcebook in one. The replacement über evil to the death of the dragon was a perfect choice.
The Ivory Triangle
I only wished more cities had been given the awesome details Gulg and Nibenay were in this set. All of the Dark Sun accessories I break out to read over again and again.
Mind Lords of the Last Sea
I'm highly certain that Mind Lords was a fantasy/Dark Sun twist on the 60s TV show called The Prisoner. I asked the author about it . . . and got a sly nondenial response that it was certainly plausible.
Dragon's Crown
Freedom
Road to Urik
Asticlan Gambit
Merchant House of Amketch
Forest Maker
Black Flames
Marauders of Nibenay
Black Spine
The flipbook format of the above adventures was very clever, but clearly expensive for TSR. It is no wonder it was jettisoned in later adventures. The inclusion of short story booklets in the boxes is something that I with WotC would do today.
The People of the Land miniatures set (x3)
Light War Chariot miniatures set (x4)
There was no reliablly "Dark Sun-ish" figurines anywhere, so I bought extras of the few there were! There were no Crodlu minis anywhere except in the Light War Chariot box, so I bought enough for a heard of Crodlu! *giggle*
Ravenloft
Castles Forlorn
Grim Harvest
A Light in the Belfry
Not sure why I got all these. I know part of it was my love of Azalin. Awesome bad guy. He could use more detail. Castles Forlorn and A Light in the Belfry I picked up in the used bin for a few bucks each.
Generic
Battle System
I hoped to make use of this, especially with the H1-4 Bloodstone series. Never got to.
Dragon Mountain
Never got to use. Will be eBayed soon.
Night Below
I refer to this for how to start a long term campaign and build it into a lengthy epic.
Castles
I picked this up purely because it had Castle Hart (in Greyhawk) in detail with a fantastic poster.
Strongholds
Wished I hadn't bought it.
Deck of Psionic Powers (x2)
I bought extras for my Dark Sun campaigns for all my players to have enough.
Deck of Wizard Spells
Never used.
Return to the Tomb of Horrors (not for much longer)
On my eBay pile right now.
Will
Mayfair Games count? If so . . .
Demons (all of them)
Sentinals
Arch Magic
Apocalypse
I've considered eBaying all of these except for Apocalypse. I may someday if I can bear the thought of parting with these collectibles.
Oy. I have a little collector habit going it seems.