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.
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