thenbrent

findingsimple

Allow site admins to restrict the tags available for other users on their site.
Admins can also restrict the items for custom, non-hierarchical taxonomies.
This plugin changes the Post Tag UI on the Edit Post admin page to be similar to that of the Categories UI. Checkboxes for previously defined tags are presented instead of a text field.

Restricted Tags

Using this plugin, Administrators can define tags, which are then the only tags visible for Authors, Editors & Contributors when editing a blog po …

Amaury Balmer

WordPress 3.1 and up allow for reasonably simple custom taxonomy, this plugin makes it even simpler, removing the need for you to write any code.
Add support for taxonomy with or without hierarchical. Choose the selector type for write post.
Allow to add taxonomy to any objects registered on your installation. This plugin can be coupled with the plugin ACF to a new term meta database that allow to create on fly any field need for the taxonomy. For example, for a “Number” taxonomy, you can add fields : number ID, date of parution, screenshot, etc !
This plugin is developped on WordPress 3.5, with the constant WP_DEBUG to TRUE.
This plugin allows you to add taxonomy just by giving them a name and somes options in the backend. It then creates the taxonomy for you, takes care of the URL rewrites, provides a widget you can use to display a “taxonomy cloud” or a list of all the stuff in there, and it allows you to show the taxonomy contents at the end of posts and excerpts as well. 
To boot, it comes with a set of template tags for those who don’t mind adapting their own theme.
For full info go the <a href="https://github.com/herewithme/simple-taxonomy" rel="nofollow ugc">Simple Taxonomy</a> page.

Simple Taxonomy

WordPress 3.1 and up allow for reasonably simple custom taxonomy, this plugin makes it even simpler, removing the need for you to write any code.

Restricted Tags vs Simple Taxonomy