Hexagon UI for iPhone by azariel87 on deviantART
Domantic App UI / Emilie Deneuvelaere
AR Energy Monitoring UI by Kingyo A part of augmented reality energy monitoring conceptual design.
Flat + Transparent UI :: A simple flat UI kit. These transparent elements will work great over photos and dynamic backgrounds! All buttons, fields and graphics included are also scalable. These are 100% free for personal and commercial use.
Modern Website Design
Dribbble - My Digital Plate Fix by Adam Deutsch
Not a fan of UI "kits," but this is a nice idea.
Wood & Metal UI - GraphicRiver Item for Sale