Dan Griffiths

Adds a robust third-party product system to Easy Digital Downloads. When activated, adds new fields to the Download Prices meta box allowing you to specify redirect details.
External Products is based on the extension of the same name by WebDevStudios.

Easy Digital Downloads – External Products

Was looking for exactly this: an option to add third party plugins on my own EDD shop. 

Perfect

Adds a robust third-party product system to Easy Digital Downloads

Mike Lee

Turn your WordPress site into a third party for authentication services.
Features
<ul>
<li>Registration and login with Facebook, Google and Twitter.</li>
<li>Simple to setup and use.</li>
<li>Record user connections in a table with data filtering and csv export.</li>
<li>Display your authentication buttons in any page with widgets.</li>
</ul>
API
<ul>
<li>Create session: DigilanToken::initialize_new_connection()</li>
<li>Authenticate: DigilanToken::authenticate_ap_user_on_wp()</li>
<li>Validate: DigilanToken::validate_user_connection()</li>
<li>Delete user data: DigilanTokenUser::forget_me()</li>
<li>Configure: DigilanTokenActivator::get_ap_settings()</li>
</ul>
Usage
<ul>
<li>Configure your social providers.</li>
<li>Add your social authentication buttons with a shortcode or a widget. 
** To display for example google and facebook given the fact you configured those two providers: 
[digilan_token google=”1″ facebook=”1″]</li>
<li>To use the plugin as a widget, go to “Appearance > Widgets” in the admin panel.</li>
<li>Under “Available widgets” section find “Digilan Token Buttons” and “add widget”, then select the providers you want to display.</li>
</ul>

Digilan Token

This plugin helps transform a WordPress into a third party authenticator services.

Easy Digital Downloads – External Products vs Digilan Token