Summary: Learn to find permissible event log keywords values with Windows PowerShell.

 How can I use Windows PowerShell to find examples of keywords when I use a FilterHashTable value
          with Get-WinEvent?

 Create an instance of the StandardEventKeywords enumeration, and then look at the Static properties:

[System.Diagnostics.Eventing.Reader.StandardEventKeywords] | gm -s -MemberType property