Hi,
Could you please clarify whether you want to display documents of certain type or anything else? What exactly do you mean by "displaying page templates"?
You can display the content of the documents using proper
transformation.
If you wanted to display page miniatures (thumbnails) in the slider, you would probably need to add for example an image field to the document type (there probably the CMS.MenuItem) to store the thumbnails within documents and display them in the transformation used in the content slider.
Any further details would be helpful.
Regards,
Zdenek