Which File Types to Keep in the Installation Folders

Setup and Customization Question:

Besides the application .EXE file, which files, if any, do you reference that are recommended to be kept in the installation path?

Perhaps it would be easier to list which types of files you customize and store in a directory structure outside of the installation path?

Screenshots or other example types are appreciated.

Always had customized server located files so that all users could access them. cfg files per project kept in the project folder, the prj file per project kept in a dedicated spec folder on the server. Basic reference files for steel, P&ID library, and HVAC remained reference to the install, of course all the install locations had to be the same on each machine. If anything were customized, it was moved to the server and paths corrected in the cfg files.