Library/Printers/PPDs/Contents/Resources/ Canon iPF8300(CUPS) Library/Printers/PPDs/Contents/Resources/ Canon iPF6350(CUPS) Library/Printers/PPDs/Contents/Resources/ Canon iPF6300S(CUPS) Library/Printers/PPDs/Contents/Resources/ Canon iPF6300(CUPS) Library/Printers/PPDs/Contents/Resources/ Canon D460-490 Library/Printers/PPDs/Contents/Resources/ Canon D400-450
A sample of the output: MacBook-Pro:~ user$ lpinfo -m lpinfo -m will parse any valid PPDs found if it doesn't have a PPD that CUPS can parse, then it isn't a valid print driver.
CUPS specifies that drivers can consist of an arbitrary number of files, but they must all be declared in a central PPD file. The only authoritative list of available print drivers on OS X is that returned by lpinfo -m (specifying the host is not necessary for the local machine). While drivers are typically found in /Library/Printers, the folder can contain support files and many other things which are not themselves print drivers, and in the real world there is no canonical location within the folder where the actual driver files are stored. Since Mac OS 10.2, printing is handled by the CUPS system.