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.

David Tufts

J Andrew Scott

brettgfitzgerald

This version is a beta pre-release, all functions and variables are subject to change without notice. Please report any issues to help make this a better product.
This plugin addresses many features that WordPress does not have out-of-the-box but that are interrelated in some way and should be included in one plugin as these features need to play well together. Here is a list of some features:
For Administrators
<ol>
<li>Allows for point-and-click post type management</li>
<li>Adds user roles and capabilities control</li>
<li>Adds content publication workflow</li>
</ol>
For Designers
<ol>
<li>Has an expanded multi-view template architecture, e.g. For Events, “Day View”, “Week View”, “Month View”, “List View”</li>
<li>Adds robust navigation, pagination, and taxonomy widgets</li>
<li>Adds advanced filtering and sorting</li>
</ol>
For Developers
<ol>
<li>Uses session-based data storage</li>
<li>Has object relationships (a la group-members, user-favorites, etc)</li>
<li>Turns your WordPress install into an public API</li>
</ol>
<ul>
<li>Adds a ReSTful API to any WordPress install</li>
<li>Uses OAuth authentication for remote API access</li>
<li>Object-oriented resource controllers (post type modules)</li>
<li>Post meta-types: people, items, locations, events</li>
</ul>

KickPress

KickPress gives your WordPress website a full featured API, including remote access authentication for 3rd party websites and mobile apps.

Simple Taxonomy vs KickPress