Courtesy of your friendly, neighborhood Microsoft PFE
Mr. Ashley McGlone
This script creates a report of all group policy links, their locations, and their configurations in the current domain, and their replication metadata for auditing and forensics. Output can be piped to a CSV file, Out-Gridview, etc.
tl;dr - It shows you where all of your GPOs are linked to the OUs and where blocking or no-override is turned on. It also shows you forensics data like when it was last linked or edited.
Call this script like this:
.\gPLinkReport.ps1 | Out-GridView
.\gPLinkReport.ps1 | Export-Csv -Path .\GPLinkReport.csv -NoTypeInformation