Kite

Due to security/privacy concerns, JSON REST API (WP API) only allows post meta data (custom field value) for authenticated users. 
This plugin is an easy way to make post meta available when unauthenticated.
After activate the plugin, go to WP API Customizer option page. 
Click the plus icon to add rows. 
Set JSON attributes and custom field names in your posts that you want to use when unauthenticated. 
The JSON REST API will provide the data as “post_meta” like the following:
<pre><code>"post_meta":{"your_attribute_a":"Custom Field A value","your_attribute_b":"Custom Field B value"}
</code></pre>

WP API Customizer

Make post meta data (custom field values) available for JSON REST API (WP API) when unauthenticated.

XYDAC

This plugin is an Easy to use Taxonomy Manager to Customize Taxonomies and its Custom Fields, with great UI. 
<a href="https://downloads.wordpress.org/plugin/ultimate-taxonomy-manager.zip" rel="nofollow ugc">Download now!</a>.
<a href="http://taxonomymanager.wordpress.com/" rel="nofollow ugc">[Plugin URL]</a> | <a href="https://xydac.wordpress.com/2010/09/30/ultimate-taxonomy-manager-for-wordpress/" rel="nofollow ugc">[Tutorial]</a> | <a href="https://posttypemanager.wordpress.com/" rel="nofollow ugc">[Ultimate Post Type Manager]</a>
[[An upgrade of this plugin is <a href="https://wordpress.org/extend/plugins/ultimate-cms/" rel="ugc">[WordPress Ultimate CMS]</a>, Please upgrade to WordPress Ultimate CMS.]]
Some Features
<ul>
<li>Create Custom Taxonomies.</li>
<li>Customize every detail of Taxonomy.</li>
<li>Create Custom Fields for Taxonomy.</li>
<li>Show Taxonomy as Combobox on New post/Custom Post type page(Provides ability to select only single Taxonomy).</li>
<li>Create same Taxonomy for multiple Post types.</li>
<li>Manage Custom fields for all taxonomies registered (Except Media).</li>
<li>Supports creation of custom fields as Text Box,Combo Box.</li>
<li>Easy to use interface.</li>
<li>Short codes to display custom values wherever you want to display.</li>
<li>Allows Modifying Custom Fields for all Registered Taxonomies even for Category and Post Tags.</li>
</ul>
<h4>Update</h4>
<ul>
<li>Updated to Support View Item</li>
<li>Added Bonus Tweak to Add Default WordPress Categories to Pages.</li>
<li>Added Feature to Select permission based on User Role</li>
<li>Update Count Callback Function Name input for advanced users.</li>
<li>Added Jquery Support</li>
<li>UI Improved</li>
<li>Add Images to any Taxonomy say Category,Post-tags anywhere</li>
<li>UPDATED TO SUPPORT WORDPRESS MULTISITE</li>
<li>Filters shown on Post page</li>
<li>All taxonomies shown on Post page in columns.(Use screen option to customise)</li>
</ul>

Ultimate Taxonomy Manager

This is an Easy to use Plugin to Create, Customize, Manage Taxonomies as well as Manage its Custom Meta Fields. Now add images to category/tags.

WP API Customizer vs Ultimate Taxonomy Manager