Pete Mall

Adds advanced plugin installation options to WordPress. Allows the user to install the development version of a plugin. Adds a link to the top of the plugin install page to install the development version of the plugin. If the development version is not available then a message is displayed at the top of the plugin install page.

WP Plugin Installer

Allows the user to install the development version of a plugin for testing purposes.

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.

WP Plugin Installer vs Bulk Plugin Installation