I am sure you know the feeling, that you would like to fully utilize that application bar on Windows Phone 8 but you haven't found the right icon for your particular button ... been there, done that. Then it is time to look at the character map and keep scrolling until you find what you were looking for. But even then you might still be looking for further icons.
Pedro Lamas - Development specialist for Windows Phone - has created a little package with 99 application bar icons that you can use free of charge.
You can find it here - the following image shows you the available icons:
Thank you! I was in need of some good icons, and these are perfect.
Glad you like them! :)