There are very very few stand-alone adventures for 2e that were good. I should know - I have a farily ample collection of them, and semi-recently I converted all of them to 3e. Bleh. The ones that are pretty good, IMO (that immediately come to mind):
- Night Below
- Return to the Tomb of Horrors
- Gates of Firestorm Peak
- Dead Gods
- Return to White Plume Mountain
- most if not all of the Al-Qadim adventures
- Shattered Circle
- I'd add Axe of the Dwarvish Lords, but it was awful in 2e with the idiotic made-up rules for goblins. However, it converts and runs very well in 3e, ironically.
The best 2e adventures, by far, are those in Dungeon Magazine. The difference between the 2e Dungeon Mag adventures and the 2e stand-alone modules are absolutely astonishing. Most of the era of 2e Dungeon was flat-out excellent.
(The worst 2e adventures is the entire Ravenloft line, less Feast of Goblyns and Ship of Horrors. The rest of the Ravenloft modules are the reason wny 2e gets such a bad rap. Deservedly so, I might add. Ravenloft modules = unplayable crap, AFAIC.)