update: the programs work, the files i was trying to open do not.
https://archive.org/details/3DO-Content-Library
this collection of 100-some CDs (and a further 140 not yet dumped, apparently?!) is what i was targeting - the discs are meant for a Macintosh (since that's what the 3DO development toolkit ran on!), but beyond getting the CD Browser and Text Index to start (and then crash when I search for anything!), I can't figure out how to browse it at all.
Through some hex-editing I've at least learned that the Clip Art collection seems to be in some version of Adobe Illustrator (hence my installing CS2 to attempt to force-feed it those files), and the sounds are allegedly uncompressed, but I'm unable to get anything to load even with that knowledge. I think these are in container formats that the CD Browser would know how to work with. If only the Browser didn't crash all the time.
I can at least glean some things from reading the other files on the CD Browser disc; there's an Excel spreadsheet on there with the names, addresses, and phone numbers of all contributors to the Content Library. This includes dozens of photographers, a well-known clip-art library, Sound Ideas (best known for producing the sound library used in Doom), and multiple stock video libraries, including Prelinger.
I would assume, the same Prelinger as this one: https://archive.org/details/prelinger?tab=about
By all of that, I can make an informed assumption about what the 3DO Content Library really is: a ready-made compilation of existing libraries of assets, images, sounds, music, and video clips, provided by the 3DO Company to its licensed developers. Perhaps its container formats are specifically formats already meant for use with the 3DO hardware, to remove the need for conversion?
Such a collection existing would certainly explain a lot about some 3DO games' aesthetics. Videos and all.