Mailbox for Mac buttons show the keyboard shortcuts when the ⌘ key is pressed.
Fun Buttons by Eddie Lobanovskiy.
Tempo by jxnblk (animated opacity and sizing effects on hover)
Windows 8 CSS buttons
Music Player with Sketch file by Meng To
Clothing Conversions by Ben Cline
Tweet button by Meng To
Things for Designers
Polaris UI Kit w/ PSD
Add to Cart buttons w/ PSD
Camp Basecamp iPhone app
Vestas Mobile CVI
Quickscan button by Jonathan Moreira