LordPretender

This plugin allow you to add files into your media library without having to upload them. So, you will be able to share, for example, your files into your Google Drive. 
This also save you steps to download the image to local computer and upload again to your own WordPress.
<h4>Features</h4>
<ul>
<li>Automatically downloads and adds the file to the media library.</li>
<li>After the uploading is successful, you are redirected to the edit screen</li>
<li>A new dropdown list is available in the media library to let you display only uploaded files, not uploaded files, …</li>
</ul>

Add Media from URL

large chunks of code taken from the much better original here:

https://en-au.wordpress.org/plugins/lh-add-media-from-url/

IMO it unethical to use this plugin

A crappy clone of the original

Let you add media files into your media library without having to upload them.

Matthias Pfefferle

Adds OExchange and Web Intents support to WordPress’ “Press This” bookmarklet (http://oexchange.org).
Supported Plugins:
<ul>
<li>the webfinger-plugin: <a href="https://wordpress.org/plugins/webfinger/" rel="ugc">https://wordpress.org/plugins/webfinger/</a></li>
<li>the host-meta-plugin: <a href="https://wordpress.org/plugins/host-meta/" rel="ugc">https://wordpress.org/plugins/host-meta/</a></li>
</ul>
From the website:
<blockquote>
This’ll help you get up and running, whether you’re a service that can accept content, a site that has content to share, or a tool of some sort. Remember that OExchange isn’t limited to “sharing” things; it applies to any case where one service wants to send URL-based content to another — microblogging, translating, printing, whatever.
</blockquote>

OExchange

Adds OExchange and Web Intents support to WordPress

Add Media from URL vs OExchange