Following PowerShell CMDLET will give you a list with grey agents in your SCOM environment.
$rootMS=”<RMSFQDN>”
# Add operations manager snapin and connect to the root management server.add-pssnapin “Microsoft.EnterpriseManagement.OperationsManager.Client”;
set-location “OperationsManagerMonitoring::”;
new-managementGroupConnection -ConnectionString:$rootMS;$WCC = get-monitoringclass -name “Microsoft.SystemCenter.Agent”
$MO = Get-MonitoringObject -monitoringclass:$WCC | where {$_.IsAvailable -eq $false}
$MO | select DisplayName
$MO | measure-object