Well I don't care so much about versions, but rather what all the different programs are.
So far we've got:
-TurboSynth
-Sound Tools II
And now Charles adds:
-Sound Designer
-Softsynth
It seems they are all sample generating/editing apps. I vaguely remember them doing a sequencer for ST but maybe I'm wrong?
The Digidesign website has a legacy download section with old files but it only offers certain stuff and it's mostly Mac and some PC. Too bad

Keep the Digidesign info coming. I think it will be a great thing to add to the wiki.