The following PowerShell script will loop through all the lists in a given site and look for a particular content type.  This is useful if you ever need to report on how many lists are using a content type, or you're just curious.

This script takes 2 arguments:

So using the script would look like the following:

A complete walkthrough is available here:  http://brandonatkinson.blogspot.com/2013/07/find-lists-or-libraries-using-content.html

The script above has the following code:

PowerShell
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###############################################################################   
##  ADD IN SHAREPOINT SNAP IN IF NOT ALREADY LOADED ##   
###############################################################################   
   
if ((Get-PSSnapin "Microsoft.SharePoint.PowerShell" -ErrorAction SilentlyContinue) -eq $null) {   
    Add-PSSnapin "Microsoft.SharePoint.PowerShell"   
} 
 
 
###############################################################################   
##  SET VARIABLES FROM ARGUMENTS ##   
###############################################################################   
  
$webUrl = $args[0]  
$ctName = $args[1] 
  
# Varibale to hold document count  
$count = 0  
 
 
###############################################################################   
##  PERFORM SEARCH ##   
###############################################################################   
 
# Get site instance 
$site = get-spsite $webUrl 
 
# Formatting 
Write-Host "" 
Write-Host "Starting search...." 
Write-Host "" 
 
# Loop through each web in site, then each list 
foreach ($web in $site.AllWebs)  
 { 
   foreach ($lst in $web.lists)  
   {  
     foreach ($ctype in $lst.ContentTypes)  
     {  
           if ($ctype.Name -eq $ctName)  
           {  
        Write-Host $lst.DefaultViewUrl -ForegroundColor Yellow 
        $count++ 
    } 
     } 
   }  
   $web.Dispose()  
 } 
 
# Formatting 
Write-Host "" 
Write-Host "Found $count lists using the content type '$ctName'." -ForegroundColor Green