Looks for all items with specified template name that have a value in the specified field

FindAllItemsByTemplateWithValueInField.ps1

$root = gi master:// -id "{C557F52C-BDBA-4F3D-BAD0-E315AD39C9CB}"
$items = $root | ls -r | ?{$_.TemplateName -eq "<TEMPLATE NAME>"}
$fieldName = "<FIELD NAME>"

foreach($i in $items){
    if(-not([string]::IsNullOrWhitespace($i.Fields[$fieldName]))){
        $i.Name + " : " + $i.Fields[$fieldName].Value + " : " + $i.Paths.FullPath
    }
}