Jekyll is a popular static site generator written in Ruby. I have been using Jekyll for this site since 2015. In the meantime, I had created some of minimalist Jekyll themes on my own and published them on GitHub.
The Plain
Center aligned. Single column layout. Ideal for personal blogging purpose. Made in 2015.
Thinkspace
Center aligned. Single column layout. Ideal for technical writing style blog. Made in 2016.
TextLog
Left aligned. Single column layout. No site menu in post layout. Ideal for logging notes or technical documentations. Made in 2017.