Sources of CUPS Drivers/PPDs
On the Internet you can now find many thousands of CUPS-PPD files
(with their companion filters), in many national languages
supporting more than 1,000 non-PostScript models.
(commercial, non-free) is packaged with more than 3,000 PPDs, ready for
successful use “out of the box” on Linux, Mac OS X, IBM-AIX,
HP-UX, Sun-Solaris, SGI-IRIX, Compaq Tru64, Digital UNIX, and
other commercial Unices (it is written by the CUPS developers
themselves and its sales help finance the further development of
CUPS, as they feed their creators).
(GPL, free software) provides around 140 PPDs (supporting nearly 400 printers, many driven
to photo quality output), to be used alongside the Gimp-Print CUPS filters.
TurboPrint (shareware, non-free) supports
roughly the same number of printers in excellent quality.
(LPGL, free) is a package made by IBM, now containing support for more
than 400 printers, stemming from the inheritance of IBM OS/2 know-how
ported over to Linux (CUPS support is in a beta stage at present).
HPIJS (BSD-style licenses, free)
supports approximately 150 of HP's own printers and also provides
excellent print quality now (currently available only via the Foomatic path).
(LPGL, free) from Linuxprinting.org provide PPDs for practically every Ghostscript
filter known to the world (including Omni, Gimp-Print, and HPIJS).