Create a random set of items using Sitecore PowerShell Extensions.

RandomItemGenerator.ps1

$selectedRootItem = Get-Item -Path "master:" -ID "{A1D0B3BC-CCDA-41FF-B59A-33AB84BF950B}"
$selectedItemTemplate = Get-Item -Path "master:" -ID "{76036F5E-CBCE-46D1-AF0A-4143F9B557AA}"
$inputCount = 100
$itemNamePrefix = "DeleteMe"

$childCount = $selectedrootItem.Children.Count + 1
$createdItems = [System.Collections.ArrayList]@()
$totalItemCount = $childCount + $inputCount
for($index = $childCount; $index -lt $totalItemCount; $index++) {
    $createdItem = $null
    if($index -lt 10 -or $index % 50 -eq 0) {
        $createdItem = New-Item -Path $selectedrootItem.ProviderPath -Name "$($itemNamePrefix)$($index)" -Type $selectedItemTemplate.Paths.Path
        $createdItems.Add($createdItem) > $null
    } else {
        $randomIndex = Get-Random -Minimum 0 -Maximum ($createdItems.Count - 1)
        $rootItemPath = $createdItems[$randomIndex].ProviderPath
        $createdItem = New-Item -Path $rootItemPath -Name "$($itemNamePrefix)$($index)" -Type $selectedItemTemplate.Paths.Path
        $createdItems.Add($createdItem) > $null
    }
    
    Write-Progress -Activity "Creating new items" -Status "Created $($createdItem.ProviderPath)" -PercentComplete ($index/$totalItemCount*100)
}

Write-Progress -Completed -Activity "Done."