GromBeestje

The OAuth plugin for WordPress allows you to provide authentication against any 
OAuth provider. This plugin is uses the OAuth library by Manuel Lemos. The 
plugin allows the admin to select any from the services supported 
out-of-the-box by the said library. Additionally it is possible to configure a 
service manually, which means any site supporting the OAuth protocol can 
be used.

BlaatLogin: OAuth

This plugin turns your WordPress website into an OAuth Consumer. It allowsallows your users to sign in with any OAuth provider.

Parth vataliya

Ultra minimal plugin to let your users login to WordPress applications using their GitHub accounts. No more remembering hefty passwords!
<h3>Initial Setup</h3>
<ol>
<li>
Create a project from <a href="https://github.com/settings/developers" rel="nofollow ugc">GitHub Developer Settings</a> if none exists.
</li>
<li>
Go to OAuth tab, then create credential for OAuth client.
<ul>
<li>Add <code>YOUR_WEBSITE_NAME</code> in Application Name</li>
<li>Add <code>YOUR_DOMAIN/HOME_URL</code> in Homepage URL</li>
<li>Add <code>YOUR_DOMAIN/wp-login.php</code> in Authorized redirect URIs</li>
</ul>
</li>
<li>
This will give you Client ID and Secret key.
</li>
<li>
Input these values either in <code>WP Admin > Settings > Login With GitHub</code>
</li>
</ol>
<h3>How to enable automatic user registration</h3>
You can enable user registration by 
– Enabling Settings > Login With GitHub > Enable GitHub Login Registration
Note: If the checkbox is ON then, it will register valid GitHub users even when WordPress default setting, under
Settings > General Settings > Membership > Anyone can register checkbox
is OFF.

Login with GitHub

Minimal plugin that allows WordPress users to log in using GitHub.

BlaatLogin: OAuth vs Login with GitHub