I'm looking for a module, that creates a special sitemap for media (using the Drupal Media 2 module).
You can use the Custom sitemap for achieving this
The Custom Sitemap module allows users/site admins to add custom sitemaps to a site, unlike currently available module that binds users to build a sitemap using the primary menu.
This module enables you to add or promote random URLs from SEO viewpoint. It also facilitates you to add independent sitemaps for all domains in a multi domain Drupal setup. This also helps you to have a domain specific custom sitemap.
You can use the XML Sitemap for achieving this
For more information about this module you could go through the README.txt of this module.