Love the notes on discovering opera recordings in Phil Harris Records.
Earliest memories there have me flipping through the classical operas on RCA Victor and Victrola (their budget reissue label), Columbia and Odyssey (theirs), London and Richmond (likewise), et cetera, et cetera, et cetera.
My own big discovery was Bernard Herrmann's WUTHERING HEIGHTS, which I believe BK has reported as well. I never acquired or heard Robert Ward's THE CRUCIBLE. This shall be rectified by watching for the original LP, which is how certain things like this need to be owned and played by the likes of moi.
Fortunately, such things are often easy to find in excellent condition. The folks who bought them were usually careful with their records to the point that they often appear never to have been played -- which indeed is likely the case with some big sets like operas and recorded plays, where people sometimes listened to the first side and never moved on.