See comments section for more up-to-date versions of the script. The original script is from 2014 and will not work as is.
- Open news feed preferences on your Facebook menu (browser)
- Click people or pages
- Scroll down (or click see more) until your full list is loaded
- Run the script in your browser console
Facebook will block this feature for you while you use it, depending on how much entities you try to unfollow. It automatically unblocks in a couple of hours and you will be able to continue.
The script I posted a while back still works, just run it from within chrome/firefox dev tools console.
This script assumes that you are using a web browser to access the social media platform, specifically revealing the list of people you wanna unfollow. You can execute this script by opening the developer console in your browser while on the social media website, and then pasting and running the code.