Fluent Kit is described as 'First Fluent Design framework for web development. Based on Bootstrap 4 and jQuery' and is an website in the Development category. There are more than 10 alternatives to Fluent Kit, not only websites but also apps for a variety of platforms, including Self-Hosted solutions, jQuery, Bootstrap and CSS. The best alternative is Bootstrap, which is both free and Open Source. Other great sites and apps similar to Fluent Kit are Bulma (Free, Open Source), Materialize (Free, Open Source), UIkit (Free, Open Source) and Foundation (Free, Open Source).
Flat UI Pro is made on the basis of Twitter Bootstrap in a stunning flat-style, and the kit also includes a PSD version for designers. Flat UI Pro contains a huge number of basic components, icons and glyphs.