It’s always a good practice to keep a VDI estate in a good managed manner. Unused VDIs are not so easy to locate with the provided out-of-box View Administrator capabilities. Such VDIs can often appear when people leave and if not a good working leaving process exists.
In some of the environments I was tasked to clean the unused VDIs and decided to automate the process.
The script will report events from all pools with a VCenter source. If data for Manual pools with physical desktops is required, just change the respective WHERE clause.