Flat UI Pro is described as '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'. There are more than 25 alternatives to Flat UI Pro, not only websites but also apps for a variety of platforms, including Self-Hosted solutions, Mac, Windows and Linux. The best alternative is Bootstrap, which is both free and Open Source. Other great sites and apps similar to Flat UI Pro are Materialize (Free, Open Source), UIkit (Free, Open Source), Semantic UI (Free, Open Source) and Purecss (Free, Open Source).
400+ material UI elements, 600+ material icons, 74 CSS animations, SASS files, templates, tutorials and many more. Free for personal and commercial use. Trusted by 1 000 000 + developers & designers. Used by such companies as Nike, Samsung, Amazon, Ikea, and Sony.
Kube is one of the world's most advanced and flexible frameworks. Kube helps you spend less time on routine tasks and more time creating amazing products. Focus on success, and Kube will cover the technology behind it.
Pixel Lite Bootstrap 4 UI Kit is a beautifully crafted UI Kit based on Bootstrap 4 Components. This theme was built following Bootstrap's methodologies by the heart. It has 100 components, 3 plugins and 3 example pages.