Find items that have a Rendering that uses a particular parameter

Find Rendering By Parameter.ps1

foreach ( $item in Get-ChildItem -Path master:/sitecore/content/Home -WithParent -Recurse )
{
    $params = @{ "paramName" = "*" }
    $renderings = Get-Rendering -Item $item -Parameter $params
    
    if ($renderings.Count -gt 0)
    {
        # This item has a rendering with the parameter
        $item.FullPath 
    }
}