Not a fan of UI "kits," but this is a nice idea.
Google Music Mini-Player (PSD)
Dribbble - app card by Beard Chicken #UImotion
Stark contrast example of Data Viz — leveraging light & dark backgrounds to showcase data. Also, looking at the corner-radius of the containers and custom typography to make things look more 'appy'
Inspired UI - Mobile Apps Design Patterns [Android]
Flat Music Player (iOS) by Michal Langmajer