Here you can download a number of older Scratch files, both during Scratch's development, Scratch's Flash rewrite's development, Scratch release versions, and versions of "Net Scratch"-- a leaked version which was intended to have the ability to retrieve random trivia from the internet. The origins of the October 11, 2003 version are less certain, but is still included here for completeness.
Available images:
The October 2004 build is the oldest still available for download directly from MIT servers at https://llk.media.mit.edu/courses/software/scratch/ (archived version- this was online for an amazing 17 years but has been pulled offline as of 2022-01-23)
This version contains a plentiful amount of information, including the October 2004 build, some sample projects in that version, and a large amount of documentation. Five other pre-release versions are available but only in .image files. A number of sample projects from 2006 are available at https://web.media.mit.edu/~jmaloney/mit_scratch/

No rights or ownership is claimed of the images provided here - all rights belong to the Scratch Foundation