If you want to delete PPD files, runs a file search for *.ppd in Finder or Explorer (you may need to include hidden files).
But PPD files in and of themeselves should not be adding printers to the list. ID should only list printers that are actually installed on the system (and you should not be able to select a PPD for an installed printer -- ID does that automatically) so the only place you'd see a loong list of printer descriptions would be when printing to PDF or Postscript File. If you have too many printers in your list, uninstall the ones you don't use.
That large list of printers that appear, are not ones i have created/installed on the network. It seems that they are preinstalled drivers from the system to make it easyer to select new printers etc.
To be frank this question i made, probably isnt written well, perhaps what i should be asking is, why does the print dialogue button take so long to appear? I thought that this was due to the long list of printer drivers that appear in the system. So i was looking for a way to delete them, in order to shorten the time it takes for the printer dialogue to open!
Did i help?
If these are network printers you should talk to the IT people and ask them to remove them from your system unless you actually print to them.