They have pretty much every record ever recorded, in every release, in every country. If you have a release you think is rare, the buyer might ask you about the "dead wax", the writing on the space near the label after the last track. You can accept bids on it. They know all about shipping costs. I found it all to be a very pleasant experience.
But it would be nice if the used book market stayed old-fashioned.
See my other reply to you about bibliographies. There isn’t a central repository because we’re talking about millennia worth of very messy data [1]. Instead we have to first find a bibliography (usually itself an old or rare book from the same decade or century), make sure its not full of shit, then use that to identify the books we’re actually interested in.
Edit: should have added a disclaimer that I collect books that were published before the ISBN was a thing. There’s definitely an ISBN database
[1] collecting pre-Gutenberg manuscripts is insanely fun, hard, and eye wateringly expensive