Flat UI Kit by Riki Tanone (free)
Flat UI Kit (PSD) by Devin Schulz (free)
Eerste UI Kit (free)
Metro UI kit (free)
Ui Kit by Abhimanyu Rana (free)
Flat Ui Kit by Zachary VanDeHey (free)
FREE flat UI kit by Visualcreative.cz (free)
UI Kit (PSD) by Piotr Kwiatkowski (free)
Vertical Infinity (free)
Flat/UI Kit by Sebastiaan Scheer (free)
Flat UI Kit by Jan Dvorak (free)
Flat Design UI Concepts (free)
UI/UX Kit (free)
Flat Bold UI Kit by Simon Eramo (free)
UI Kit by Huseyin Yilmaz (free)
Splash of Color Premium Kit (free)
Flat UI Kit by Design Modo (free)
Drops Flat UI Kit ($5)
Pixels Flat UI Kit ($9)
Atom UI ($10)
Night Sky Theme ($18)
Flat Stroke UI Kit ($8)
Square UI ($39)
UI Kit – Flat Design ($8)
Flat UI Kit ($6)
Ultimate Flat UI Kit ($6)
Flat UI Kit ($4)
Metro UI Responsive Admin Template ($16)
via webdesignerdepot