來源： http://www.uisdc.com/the-ultimate-guide-to-flat-design
Featherweight UI (free)http://sarahjustine.com/2013/03/17/featherweight-ui-a-free-vector-based-and-retina-ready-ui-kit-with-bonus-mini-tutorial/
Polaris UI kit (free) http://designmodo.com/polaris-free/
Erste UI kit (free)http://www.designyourway.net/blog/resources/eerste-flat-user-interface-kit-that-is-free-to-download/
FlatUI kit (free)http://www.webdesignerdepot.com/2013/05/flat-ui-kit-free-download/
Flat UI (free)http://designmodo.github.io/Flat-UI/
Flat UI kit (free)http://dribbble.com/shots/947782-Freebie-PSD-Flat-UI-Kit
Metro UI kit (free)http://www.tempees.com/free-download/metro-ui-kit
Monotone flat UI kit (free)http://dribbble.com/shots/1061304-Freebie-PSD-Flat-UI-Kit
Vertical Infinity (free)http://www.cssauthor.com/vertical-infinity-a-mega-flat-style-ui-kit-for-free-download/
Lil UI kit ($6)https://creativemarket.com/lilsquid/5455-Lil-UI-Kit-PSD-Vector-UI-Library