I used Novell DOS 7 back in its day and squeezed > 70 MB on my 50 MB hard disk drive thanks to its Stacker disk compression feature. I remember it coming in a flashy red colored box. It also supported to move most drivers into extended memory to have much more conventional memory available on 386 machines. However, most cutting edge games used DOS protected mode extenders already, so for gaming you couldn’t use that feature.

Great times, anyways. ;)