Features Extra provides faux exportables (via Features) of several site-building components.
Drupal 6: Supports exporting taxonomy vocabularies. To export a vocabulary, install FE taxonomy, go to vocabulary edit page, assign it a "machine name," then export it with Features as usual. As a bonus, this allows you to edit the "module" property of a vocabulary. Views support (by machine name) is also provided.
Drupal 7: Exporting vocabularies is supported natively by Features in Drupal 7 so it has been removed from this module. If you need to export taxonomy terms in addition to the vocabularies, you can do this with the UUID Features Integration module.
Only nodequeue definitions are supported. To export a queue, install FE Nodequeue, edit your nodequeue, assign it a "machine name," then export it with Features.
To export a block, install FE Block, edit your block, give it a "machine name," export it with Features. You can export block settings (region settings, visibility settings, ...) of any block, and the content of blocks created with the Block module from Drupal core.