Vecna and pie.
To the Aid of the Demonweb Pits - The PC's must help Lloth (and Lolth) fight off an incursion of pesky heroes.
Temple of Elemental Frog
You guys have all the classics covered, so I'll go 2e here:
Night Below Dragon Mountain
...Return to the Keep of the Apocalypse Stone (the campaign ends... again)...
Is it me, or did 2e just not have very many memorable "generic modules"? It seems like most were tied to specific campaign setting.