I'm interested in a .PGP file. I saw it on the picture and it was called BlueMatt.pgp and we know that the .pgp file is - a security key or digital signature file which can verify the user identity so I tend to believe the BlueMatt is the owner. He has a blog on bitcoin.ninja :
https://bluematt.bitcoin.ninja/about/There I found his Twitter and sent him a DM.
I tend to believe that he is the original owner of the hard drive, let's see what happens...
I wonder if OP would like to give back 30BTC because now he knows who's HDD it is. To lose 30 BTC to get some forgotten altcoins... not a good deal