What feels like a weekly response, vCenter Server Events, should always be your initial starting point in helping you understand the Who, What and When for something occurring within your vSphere environment. There are over 2K+ events that are published out of the box from vCenter Server with hundreds more from 2nd and 3rd party solutions that integrate with vCenter Server.
Combine vCenter Server Events with the power of the VMware Event Broker Appliance (VEBA), you now have a powerful Event-Driven Automation solution that can solve literally a limitless number of use cases, many of which have been shared by existing users found in this document HERE.
Today, I had received a question about auditing customers vSphere Datastore activities and identifying when someone has manually downloaded a Virtual Machine Virtual Disk (VMDK)?