Dead Gods, A Paladin in Hell, Die Vecna, Die, or the Illiathiad, or other Monstrous Arcana adventures.
Dead Gods... don't talk to me about Dead Gods. Pretty cool adventure, from 1997, so in what I'd call the "late 2E" style, but unfortunately it comes before and sets up the very worst adventure ever written, Faction War, which was a hate crime against Planescape, committed by Monte Cook, with extremely ruthlessness and violence.
Monte Cook
claims to this court that he was innocent. That Dead Gods and Faction War were "part of a trilogy" cut short by WotC's acquisition of D&D. That he "fully intended" to complete that trilogy, rather than just massively vandalizing Sigil and ruining the entire conceit that Zeb Cook (no relation, your honour) set up so beautifully. I urge you, ladies and gentlemen of the jury - do not believe Mr Cook's spurious assertions. This was hate, pure and simple, one jealous artist destroying the work of a master...
Ahem, okay getting carried away/distracted. I got "triggered" as I believe they say.
I've literally never heard of an adventure called "A Paladin in Hell" (though I am familiar with the illustration of the same title from 1E), so that's interesting (reading about it sounds like more "Monte Cook is jealous of Planescape and wants to make unnecessary changes to 1E-ify it" stuff though). Die Vecna, Die is Greyhawk so I never read it. The Illithiad is an adventure? I was just reading it like a year ago. Isn't it just a sourcebook on Illithids? Does it have an adventure as well? I could see myself blanking that because I didn't care, to be fair.
But those are all very late. The earliest one is 1997. The latest is 2000 (same year as 3E).
To me, 2E had three phases, at least, adventure-wise. At the beginning, we're basically all using 1E adventures, and updating them ourselves. Then there are the bigass 2E adventures/dungeons, from the early/mid '90s, stuff like Undermountain (1991), Menzobarranzan (1992), Dragon Mountain (1993), and The Night Below (1995). There was tons of other stuff, but it all tends to be this sort of "adventure built around an epic location", and there will always be a lot more NPCs and people to talk to and general detail and attempts to make things make more sense than 1E stuff. Then late in 2E, after I'd stopped buying adventures much, you started getting these more linear and focused adventures, like the ones you mention, the predecessors of Paizo Adventure Paths in many ways (Dragon Mountain and The Night Below were a bit like that, but not as directly).
That's like, just my opinion, though!

Unlike "Monte Cook intentionally vandalized Planescape and is a D&D criminal who should be in D&D jail", which is a hard fact that no one could possibly dispute!
