D6
CCK (D6)
- Adding a CCK Field: Learning CCK for Drupal (video) - How to create content types with input fields.
- http://drupal.org/project/filefield - robust alternative to core's Upload module and an absolute must for users uploading a large number of files
- http://drupal.org/project/search_files - allows searching for files in node attachments and in arbitrary directories. Text is extracted by externally provided helper applications.