Kitchenware is a wireframe kit provides every elements you need for creating professional and elegant iOS wireframes. Nearly 40 totally different screens covers most common iOS patterns and UI elements.
Inspirational UI Design 16 - UltraLinx
Adobe Photoshop UI Kit for Free Download
Livo UI KIT is a simple and fully customizable mobile UI Kit. Contain more than 200 screens in 8 categories.http://www.market-me.fr/Livo/
A 55+ free elements UI KIT by Polish designer Tomasz Mazurczak for personal and commercial use.