Thunder UI Kit
Flat One Page WordPress Theme. Beautiful colors. Great use of design principles. Like the layout and waypoints.
Vector inspirational - Flat Design Vectors | Vectips >> http://vectips.com/inspiration/flat-design-vectors/
Flat Colors UI Framework PSD by Designers Revolution, via Behance
A collection of flat stationery items to create great presentations for your branding projects. All objects are available...
Flat MockUps – Desk Items | GraphicBurger
Minimalistic Icons in a Flat Style by Alex Serada, via Behance
Free: PSDFest Design Asset Bundle | UI Kits, Mockups & More