I wanted to export all titles from the Plex library on my Mac and couldn't find a good tool.
This is a tiny, quick-and-dirty Node JS script, using node-plex-api.
It assumes you have node and npm installed.
Then just download this "script.js" and run:
npm install plex-api --save node script.js your_plex_username your_plex_password > plex.txt