godthor

This will create a new widget which will display your most popular posts and pages based on comment count with Disqus. Alternatively, you can use a shortcode as well.
It’s very simple to use. Just drag the widget into a sidebar and configure it, or visit the settings under the WordPress Settings menu.
Just Some of the Options:
<ul>
<li>Show featured image.</li>
<li>Choose featured image size.</li>
<li>Choose featured image alignment.</li>
<li>Show the post date.</li>
<li>Select how many days to check, IE: past 90 days.</li>
<li>Set how many posts to show.</li>
<li>Save the results for faster loading.</li>
<li>Load results using Ajax. Perfect to avoid caching results.</li>
</ul>
Note: This plugin requires you have an application registered with Disqus: https://disqus.com/api/applications/ 
It’s free and simple to setup, just follow that link.

Disqus Popular Posts

Creates a widget to show the most popular posts and pages on your site based on Disqus comments. Can also be used with a shortcode.

jp2112

Disqus is a third-party comment management system. However it loads its javascript code on every page indiscriminately. This code should only be loaded on pages where the comments form is actually going to load. Otherwise your site is wasting cycles including javascript that isn’t going to be used.
This plugin stops the <a href="https://wordpress.org/plugins/disqus-comment-system/" rel="ugc">Disqus plugin</a> from loading its javascript on pages or posts where comments are closed. If comments are closed and there are no existing comments already, the JavaScript will be stopped from loading. Note that to avoid breaking the existing functionality, the JavaScript will still load if comments are closed but there are already some comments on a page/post.
Based on http://thomasgriffinmedia.com/blog/2012/11/tame-disqus-comments-in-wordpress/
Disclaimer: This plugin is not affiliated with or endorsed by Disqus.
<h3>If you need help with this plugin</h3>
If this plugin breaks your site or just flat out does not work, please go to <a href="https://wordpress.org/plugins/disqus-conditional-js-load/#compatibility" rel="ugc">Compatibility</a> and click “Broken” after verifying your WordPress version and the version of the plugin you are using.
Then, create a thread in the <a href="https://wordpress.org/support/plugin/disqus-conditional-js-load" rel="ugc">Support</a> forum with a description of the issue. Make sure you are using the latest version of WordPress and the plugin before reporting issues, to be sure that the issue is with the current version and not with an older version where the issue may have already been fixed.
Please do not use the <a href="https://wordpress.org/support/view/plugin-reviews/disqus-conditional-js-load" rel="ugc">Reviews</a> section to report issues or request new features.

Disqus Conditional JS Load

Stop the loading of Disqus Javascript on pages/posts where comments are closed or not available.

Disqus Popular Posts vs Disqus Conditional JS Load