With these frameworks you have easily a lot of good buttons options. It is specially useful for back-end developers, that always need some pretty buttons, but don’t have time (or budget) to do so.They are all CSS3 ready, and can be easily customized.
CSS3 Buttons is a simple framework for creating good-looking GitHub style button links.
The Buttonize Framework is a simple, light-weight CSS file with precompiled styles and colours for quick, modern looking buttons. It uses CSS3 for rounded corners and subtle gradients but with bulletproof fallbacks for older browsers.
There was a goal: Create CSS buttons that are sexy looking, really flexible, but with the most minimalistic markup as possible.
Sexy Buttons is a HTML/CSS-based framework for creating beautiful web site buttons. These stylish, attention getting buttons can be used for calls to action wherever user interaction is desired. Compare Sexy Buttons with the standard browser buttons.