Mathematical Illustrations an introduction to mathematical illustrations using postscript programming language. This is one of the best showcases of postscript
Don Lancaster (tinaja.com) and his many notes on postscript publishing; Obituary.

PostScript: A Digital Printing Press | Hacker News. Main discussion about PostScript: A Digital Printing Press from the Computer History Museum article, but the HN page has lots of links to PS stuff; Dec 2022.
The origins of Postscript by John Warnock, founder of Adobe in IEEE Annals of History of Computing (2018) via gwern.
A First Guide to PostScript by Peter Weingartner. Online book.
PSChess - A Chess Engine in PostScript
PostScript® 1.0 - A Code Study | ℤ→ℤ
nasa/pvslib: NASA PVS Library of Formal Developments with 18% postscript code (among common-lisp, python etc )
nst/PSTris: A Tetris implementation in PostScript
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See also: My Hello Postscript page.