Find items with a duplicate item name at the same level using Sitecore PowerShell Extensions.

FindDuplicateItemNames.ps1

Import-Function -Name Invoke-SqlCommand

$connection = [Sitecore.Configuration.Settings]::GetConnectionString("master")

$query = @"
SELECT 
    a.[ID], 
    a.[Name], 
    a.[ParentID]
FROM [dbo].[Items] a
JOIN (
    SELECT
        [Name],
        [ParentID]
    FROM [dbo].[Items]
    GROUP BY [Name], [ParentID]
    HAVING COUNT(*) > 1
) b
ON a.[Name] = b.[Name]
AND a.[ParentID] = b.[ParentID]
"@
$itemIds = Invoke-SqlCommand -Connection $connection -Query $query -Parameters $parameters | Select-Object -ExpandProperty "ID"

$reportItems = [System.Collections.ArrayList]@()
foreach($itemId in $itemIds) {
    if(!$itemId) { continue }
    $selectedItem = Get-Item -Path "master:" -ID ([Sitecore.Data.ID]::Parse($itemId))
    if($selectedItem) {
        $reportItems.Add($selectedItem) > $null
    }
}

$reportItems | Show-ListView -Property Name, ItemPath, @{"Name"="Referrer Count"; Expression={Get-ItemReferrer -Id $_.ID | Measure-Object | Select-Object -Expand Count}}