Carbon Design System is a free set of UI kit released by IBM and available for designers and developers, as Sketch file and HTML + SCSS component library.
Free HTML UI Kits
Free HTML UI kits including tons of elements and ready to be used
Element is a complete and minimal framework based on Vue.js that includes many useful UI components to quickly build websites and apps.
Element: A desktop component UI library
Photon is an UI toolkit for building full featured desktop apps with Electron using simple HTML and CSS.
Photon – Desktop app framework
Material Design for Bootstrap is a theme for Bootstrap 3 which let you use Google Material Design in your favourite front-end framework.
Google Material Design for Bootstrap
uilang is a minimal programming language for web designers. You can easily create custom user interface components and build prototypes.
uilang – Build UI components
Bootflat is an open source flat UI kit based on Twitter’s Bootstrap 3.1 CSS framework. It provides a faster way to create elegant web apps.
Bootflat – Flat UI kit for Bootstrap
Here is a flat design user interface inspired to a PSD freebie by GraphicBurger. This HTML5 + CSS3 ready-coded template is not complete yet.
Flat design UI – HTML5 + CSS3
Responsive Flat UI kit is a ready coded HTML custom UI set built to work with and sit next to Bootstrap 3. Created by Catalin Rosu.
Responsive Flat UI kit – HTML
Flat UI Free is an awesome HTML UI kit containing a lot of useful web elements for your web projects. It has been made with Bootstrap.
Free PSD & HTML Flat UI kit
A feature-packed user interface kit containing buttons, input fields, sliders, progress bars, and various other form elements. It’s also fully coded for you in CSS and HTML.
