For digital stereo, you can pretty much find anything you’re looking for in high quality streaming with Qobuz, Idagio, or Primephonic. Unless you’re big on ownership, I don’t see a real benefit to CD hunting right now. There are some exceptions, though. For one, some labels, like Hyperion (among others), are not available online, and can only be heard by buying the CD. They do have some high quality recordings, but nothing that can’t really be replaced with other labels.
And second, most of the serious digital collecting in classical is done in SACD now. There are some high-ticket SACD recordings that are becoming scarce (the Hilary Hahn Brahms concerto comes to mind, among others), but, unless you have an SACD player and a 5.1 setup, there really isn’t any reason to go hunting for these. There are some stereo-only holy grails, also (like a lot of the early Sony’s and Telarcs), but I’ve never personally heard a difference between a stereo CD and SACD, mastering differences notwithstanding. So there’s not much incentive for investing in these, either - unless you can’t find that master, or a better one, anywhere else.
