Once again, I'm happy to share with you this soft looking interface kit! You can find a bunch of buttons, sliders, switches...
Power Buttons Freebie UI. Some pixel-perfect power buttons for your next design by by Michael Donovan.
Some Skeuomorphic buttons design experiments
UI wheel and buttons properly termed constraint buttons. Wherever an intrinsic scale is present you can be sure constraint buttons are in the mix. Further more the circle or wheel design offers economy of design
App Design for TAXI5 by Piotr Radziwon, via Behance