Enrico Sorcinelli

Taxonomies Sortable allow to sort non-hierarchical taxonomy terms associated to objects by drag&drop them on the administration interface.
<h3>Usage</h3>
Once the plugin is installed you can make a taxonomy sortable in the following ways:
<ul>
<li>Programmatically by adding <code>'sortable' => true</code> argument in <code>register_taxonomy()</code>.</li>
<li>Programmatically by using <code>taxonomies_sortable</code> filter below.</li>
<li>Using the Settings->Taxonomies Sortable administration screen by selecting non-hierarchical taxonomies you want to make sortable.</li>
</ul>
Note that making a taxonomy sortable, implicitly means also setting <code>sort => true</code> for that taxonomy.
<h3>Hooks</h3>
<code>taxonomies_sortable</code>
Filter allowing to programmatically set sortable taxonomies.
<pre><code>apply_filters( 'taxonomies_sortable', array $taxonomies )
</code></pre>
<code>taxonomies_sortable_admin_settings</code>
Filter allowing to display or not the plugin settings page in the administration.
<pre><code>apply_filters( 'taxonomies_sortable_admin_settings', boolean $display )
</code></pre>

Taxonomies Sortable

Allows to sort taxonomy terms associated to objects.

Triweb Digital

This plugin injects a small search box at the top of taxonomy metaboxes (the checkbox lists) on the post edit screen. It only appears for taxonomies that have more than 5 terms to avoid clutter.
Search queries are performed via AJAX and the checklist is filtered client-side for a quick, responsive experience.

Taxonomy Admin Search

Adds an AJAX-powered search box to taxonomy metaboxes on the post edit screen when a taxonomy has more than 5 terms.

Taxonomies Sortable vs Taxonomy Admin Search