Christian Schenk

If you’re a WordPress admin you probably want a plugin with the following features:
<ul>
<li>install, update and delete plugins and themes</li>
<li>it should be able to handle various locations, i.e. at least these <a href="https://codex.wordpress.org/Plugins#Plugin_Repositories" title="WordPress Codex Plugin Repositories" rel="nofollow ugc">plugin repositories</a> and maybe some from <a href="http://www.google.com/search?q=wordpress%20plugins" title="Google search on WordPress plugins" rel="nofollow ugc">somewhere</a> else.</li>
<li>basic search functionality for all these plugins and themes</li>
</ul>
This plugins lets you do (almost) all of these things.
Have a look at this <a href="http://www.youtube.com/watch?v=-BzX7bv3DgM" title="Introduction to Extension Manager for WordPress" rel="nofollow ugc">video</a> to see how it works.
<h3>Compatibility</h3>
This plugin was tested with PHP 5.2.x. Currently it won’t work with 
older versions, i.e. PHP 4. Please be patient until I’ve fixed that.
But it’s possible that this plugin will never work with PHP 4 because 
it’s likely that I will not find the time to implement that. So please 
consider updating your installation of PHP.
If you’d like to help me fixing compatibility issues write me an <a href="http://www.christianschenk.org/legal-notice/#contact" title="Contact me" rel="nofollow ugc">e-mail</a>.
<h3>Videos</h3>
Have a look at this <a href="http://www.christianschenk.org/projects/wordpress-extension-manager/video-for-this-plugin/" title="Introduction to Extension Manager for WordPress" rel="nofollow ugc">video</a> to see how it works.
<h3>Licence</h3>
This plugin is released under the GPL.
<h3>Translation</h3>
This plugin is available in these languages:
<ul>
<li>English</li>
<li>German (I’m working on it)</li>
</ul>
If you want to help me translating it into other languages <a href="http://www.christianschenk.org/legal-notice/#contact" title="Contact me" rel="nofollow ugc">drop me a line</a>.

Extension Manager

This plugin helps you to install, upgrade, delete and search for plugins and themes.

Cristian Beckerle

This plugin is an improvement to the current WordPress plugin installation methods. It allows you to install one or more plugins simply by typing their names or download URLs in a textarea.
All credit goes to improvingtheweb. This plugin is only a modification of <a href="https://wordpress.org/extend/plugins/improved-plugin-installation/" rel="ugc">Improved Plugin Installation</a>. The idea was to run the original plugin in the newer versions of WordPress. That’s it. Also, we cut off the bookmarklet feature.
Thank you very much for the contributions: <a href="https://profiles.wordpress.org/drewapicture/" rel="nofollow ugc">drewapicture</a>
Example
The installation form will accept any of these inputs:
<ul>
<li>Contact Form 7</li>
<li>https://wordpress.org/extend/plugins/contact-form-7/</li>
<li>https://downloads.wordpress.org/plugin/contact-form-7.3.3.2.zip</li>
</ul>
Plugins don’t need to be hosted at wordpress.org. As long as you use the direct download URL, third party plugins will install without a problem.

Bulk Plugin Installation

Allows you to install one or more plugins simply by typing their names or download URLs in a textarea.

Extension Manager vs Bulk Plugin Installation