I’ve launched a new theme directory called Built At Lightspeed with over 700 Jekyll themes. It is definitely the most up to date directory of Jekyll themes available. We’ve filtered out themes without working demos, low star ratings or that have not been updated for many years.
Nearly all the themes are free and open-source. We would like to add more premium themes, as they are important, but there a great deal available. If you have a theme that isnt listed, please reach out to me or use the “add your theme” link on the site