I didn't bother with catalogues. Living only about an hour from central London in the early 70s, it was very easy to make the trip on a Saturday to a couple of stores in the Soho area which specialised in obscure LP labels and even more obscure music: IIRC one was called Harold Stave, long gone now of course. Oh, the thrill of finding an LP of music by an unknown (to me) composer with the "right dates" (1800-1920 or so) or, even better, a new recording of music by someone who I'd already discovered and loved - Raff was the first such, but other early favourites were Glazunov (almost exclusively on those thick and heavy Melodiya discs) Rubinstein and Goetz. The Genesis, Louisville and Turnabout racks in particular were the first to be scoured for new releases. There was also a rather shifty Melodiya dealer who worked out of an unheated upstairs room opposite Foyles book shop on Charing Cross Road. Going to see him was always a rather grubby experience, but the joy of finding he had a previously unheard Glazunov symphony in stock made it worth while. Sometimes a major label would turn up trumps - Joan Sutherland and Richard Bonynge's thrilling Esclarmonde and Les Huguenots sets were my first exposure to opera (and remain favourites even now).
But nostalgia isn't what it used to be. It's easy to forget that many of those performances were cut, were of poor technical quality (Melodiya) or featured orchestras in particular which had clearly been selected for their cost rather than their quality (all those Turnabout recordings). Compared to many offerings now, the pickings then weren't only slim in number but also in quality. We have truly been living in a golden age for recordings of the unsung and, as Ilja points out, the digital age - with so many recordings both commercial and off-air freely available to listen to on YouTube - makes things almost too easy.
But nostalgia isn't what it used to be. It's easy to forget that many of those performances were cut, were of poor technical quality (Melodiya) or featured orchestras in particular which had clearly been selected for their cost rather than their quality (all those Turnabout recordings). Compared to many offerings now, the pickings then weren't only slim in number but also in quality. We have truly been living in a golden age for recordings of the unsung and, as Ilja points out, the digital age - with so many recordings both commercial and off-air freely available to listen to on YouTube - makes things almost too easy.