[tedivm]

Did you talk with VirusTotal? That's probably the largest dataset out there that isn't controlled by an AV company.

[Fnoord]

VirusTotal is owned by Google since 2012. https://virusscan.jotti.org/ is another one, even older. It says 2004, but I met that guy in 2002 or 2003 and back then he had this up already. URL might've been different.

[EdwardRaff]

I've tried. They are fairly unresponsive. Right now my advisor is trying to get an academic license to their system.