The Contact form blocks module makes your site-wide contact forms available as Drupal Blocks.
Using this module you can show your contact forms at any place where you can show a Drupal Block. For instance you may add a contact form to the right sidebar of your website which should be shown at every page. Or you want to add another contact form (aka category) to a certain node only. Add the contact form block to the content region and use the Block visibility settings to hide it from all pages but that special one.
Site wide contact form categories will be represented by one Block per category.
When using contact form categories as blocks you may not show them at the site wide contact form again. You can switch off some of the categories in the settings page of this module.