I have to say that I am a huge fan of archive.org. It has millions of things and you can find some real gems there.
For instance I have found a DVD ISO image of "Tahiti" which was also released on Laserdisc and MUSE Laserdisc.
https://archive.org/details/sony-tahiti-dvd https://archive.org/details/sony-guayanahttps://archive.org/details/sony-alaska