Here is one of the best Free Ghost Theme by GavickPro. This is a Portfolio theme with clean and flat design. Theme featured with in-built Disqus comments, Google Analytics support and featured images/videos etc…
Featured images/videos
The image or video placed at the beginning of the post will be used as a featured image/video on the post list. Additionally if you want to display the post over the title on the post page, you have to set the alternative text of the image to featured-image.
In theory you can use different images as a featured image on the posts’ list and on the post page (in this case you can add the featured-image alternative text to a different image).
The videos will be responsive thanks to the fitvids jQuery plugin.
Disqus comments
You can specify your Disqus username in the partials/config.hbs file in the following line:
var disqus_shortname = '';
Google Analytics support
You can specify your Google Analytics tracking code ID in the partials/config.hbs file in the following line:
var ga_ua = 'UA-XXXXX-X';
Background image
The image displayed in the background can be a blog cover image which can be defined in the Ghost settings. As default there is a grey background displayed.
Footer area
You can modify the content of the page footer in the partials/footer.hbs file. It will be displayed on all subpages of your Ghost blog.