If you are using the EE flow, with a Central Library, you can open Library Manager and run File -> Output PDF.
I have written a script that places every symbol on a schematic, here:
which again is based on the Central Library structure.
I am using DxDesigner, which is not using Central Library. (According to the local Mentor supporter)
Maybe the script can be rewritten.
However, I am not sure if it is possible.
I wrote one a while back that worked off a side file, I have no Idea of the state of the script but here it is with an example of the file that would list your symbols you want on the page. Maybe you can glean some pieces from it to help you. Good luck!
I have tried you script but I can't figure out how it work, there is a text file but what is it in use for.