Clean Theme is an intentionally minimalist base theme for professional WordPress developers. It is the theme that I built this website with, and it’s what I use for my own WordPress projects. It is a stripped down WordPress theme created to be used as a project starting point.
The theme includes the WordPress phpunit scaffolding, the mocha JS testing framework, the Bootstrap library, and Slick slider. There is a pre-built gulp setup to compile and minify Sass, and transpile and minify JS. All of the above can be easily ignored and/or removed if you so choose.
Clean Theme is licensed under GPL 3.0, and is completely free to use. Enjoy!