If you export your "Users and Devices" form, you will get a full list of all your devices with MAC addresses.
You can then use a switchport-mapping tool (I use Solarwinds) to get a full list of all the MAC addresses on your network.
Matching these two lists will allow you to confirm exactly which devices are still live, and also tell you where they are (assuming you have a floor plan with data port IDs marked on it).