This script is relatively simple, and I created it for my friend. In the video, I also attempted to explain the usability of the custom script and that the script/video’s usability can be viewed from different angles (skip to 6:47 in you just want to see the script).
Regarding the script, I did on purposely created the script with Python nodes so the friend and all others that find the script useful can execute from almost any Revit version without a need to install custom packages.
The script includes a small user interface in which the user needs to select any workset, and then the script will find elements that belong to that workset and select all of them.
Please make sure that before you start using this script you back up the existing project model.
Also, if you want to download this (and all other scripts) with my sample files please visit the Shop page.