This is the bunch of 3 extensions
TRUE SEO Friendly URLs with SEO Friendly Pagination including 404 error page for url manipulation

Visit to our demo site (opencart version 1.5.6): http://opencartshops.com/demo/

Following are 3 major points covered in this extension.

• 1. SEO friendly url
  like: http://opencartshops.com/demo/account/login
  http://opencartshops.com/demo/information/contact
• 2. SEO friendly Pagination URL
  like http://opencartshops.com/demo/desktops/page-2
• 3. 404 error page for URl manipulation
  In downloaded opencart
  http://opencartshops.com/demo/desktops/dfgdf
  will show the content same as
  http://opencartshops.com/demo/desktops/
  and this is duplicate page content issue
  so that to avoid this we have creaated extesnion to show 404 error page of opencart
  like http://opencartshops.com/demo/desktops/page-2/gdfgfdgdf
  will show 404 error page