To get back to the original point...for low density disks...
Everything up to 6.0.6 was on low density disks of some variety (either 400K or 800K). When the Classic, LC, and IIsi came out, Apple started using high density disks for the System Software.
There were also low density versions of the newer System 6 versions, but I haven't seen physical copies of them. Soft copies do exist--Apple has 6.0.8 on their server as four 800K disks and the 6.0.7 images are available on the System 7.0 CD-ROM.
System 7.0 was available on low density disks, as was 7.0.1 and, believe it or not, 7.1. I actually own a set of low density 7.1 disks, which even got the new labels with the black Apple logo (on lighter colored disks).
System 7.5 was high density only, but I seem to remember there was some way to get it on low density--maybe a coupon you could send in to Apple? Don't quote me on that though (my copy of 7.5 is a CD-ROM).
Nothing newer than 7.5 would be on high density disks, of course, since the Plus, SE, and II were all dropped in 7.6, and no machine made after them sold with 800K drives.
Everything up to 6.0.6 was on low density disks of some variety (either 400K or 800K). When the Classic, LC, and IIsi came out, Apple started using high density disks for the System Software.
There were also low density versions of the newer System 6 versions, but I haven't seen physical copies of them. Soft copies do exist--Apple has 6.0.8 on their server as four 800K disks and the 6.0.7 images are available on the System 7.0 CD-ROM.
System 7.0 was available on low density disks, as was 7.0.1 and, believe it or not, 7.1. I actually own a set of low density 7.1 disks, which even got the new labels with the black Apple logo (on lighter colored disks).
System 7.5 was high density only, but I seem to remember there was some way to get it on low density--maybe a coupon you could send in to Apple? Don't quote me on that though (my copy of 7.5 is a CD-ROM).
Nothing newer than 7.5 would be on high density disks, of course, since the Plus, SE, and II were all dropped in 7.6, and no machine made after them sold with 800K drives.