Balio UI Kit

The Balio UI Kit is an absolutely massive PSD file containing buttons, stickers, icons, pagination, menus, login forms and much much more. This set is offered free of charge for all WebDesign Depot subscriber (which is also free)  

UI Parade Button Builder

This button builder is a handy application, allowing people with no coding skills to create beautiful modern buttons for their websites. The application also generates the HTML and CSS code needed for the buttons to be fully functional across all modern browsers.