what is lost media YOU dont want found

It would be old hat for me to mention ones that have been said. But, off the top of my head, manifestos from mass shooters come to mind. We don't need their brain rot out there in the open or giving them the five minutes of attention they want, only for it to be cited by copycats (like the ones who credit Dylan Klebold and Eric Harris for their own crimes) later on down the line for the same reasons.

For something lesser known, the execution of Edward Heinson from 1898 is also up there. I've seen execution footage before, so when you water it down to just what it is, a hanging, that's not the issue for me. It's a lot more complex and sinister, namely with the issue of race and how it was toted around to screenings years after the fact. The exploitation genre is as old as the birth of cinema itself, which can be seen in the animal bloodsport movies from the same time, but man, this one just hits differently. From what the Wiki article said, the only known surviving reel was sold in an auction to a private collector and all we have now is a still or two. I kind of hope it stays that way.