What’s your white whale – something you’ve been looking for for years but never found?

Not quite what the OP is asking, but I had a lot of music videos recorded on Super-VHS from MTV and other sources, some of which are not available on YouTube or any other service. I had a couple dozen of these tapes back in the 1990s, all two hours long.

Those tapes were thrown away or sold for drugs, not sure which.

Some of those videos will probably never be seen by anyone again. I doubt there are any master copies extant at the studios, and if no one can unearth a copy on VHS, they are gone forever.