eggplantstudios

EPS Term/Tag Cloud Search Creates a widget that will present a “Tag Cloud” of terms, and allow you to pick one or more terms to search by – Giving you the opportunity to search for all posts that are tagged “Red” and “Blue”.
Features
<ul>
<li>Supports any publicly available post type</li>
<li>Supports any publicly available taxonomy</li>
</ul>
Created by Shawn Wernig <a href="http://www.eggplantstudios.ca/" title="Eggplant Studios" rel="nofollow ugc">Eggplant Studios</a>
This release is compatible with all WordPress versions since 3.0.1 (Tested. Plugin may not work as intended for older versions of WordPress).
This plugin is English only; though it is somewhat language independent.

Term/Tag Cloud Search

Creates a widget that will present a "Tag Cloud" of terms, and allow you to pick one or more terms to search by.

Matteo Enna

My Wine Repository

Taxonomy Meta Box Filter enhances the WordPress admin interface by adding a simple search field above each taxonomy metabox. 
It supports default taxonomies (like categories and tags), as well as custom taxonomies and custom post types (CPTs).
Perfect for sites with a large number of terms, allowing you to quickly find and select the ones you need while editing posts.
<h3>Features</h3>
<ul>
<li>Search field added to every taxonomy metabox</li>
<li>Works with hierarchical (categories) and non-hierarchical (tags) taxonomies</li>
<li>Compatible with custom taxonomies and CPTs</li>
<li>Script only loads on the <code>post</code> and <code>post-new</code> admin screens</li>
<li>Fully translatable</li>
</ul>
<h3>License</h3>
This plugin is licensed under the GNU General Public License v2 or later.

Taxonomy Meta Box Filter – Search taxonomies from the editor

Adds a search field above each taxonomy metabox in the post editor, making it easier to manage categories, tags, and custom taxonomies.

Term/Tag Cloud Search vs Taxonomy Meta Box Filter – Search taxonomies from the editor