The Decor Graphics (was Graphic Styles, then was Graphics for iWork) set contains a generous selection of high-quality designs to help you create unique Pages content or Keynote presentations. It is an excellent collection for adding some exclusivity to your slides with original bullets, characters, patterns, and image frames.
All images include transparent backgrounds that allow placing them on various colors and patterned backgrounds. You can apply the elements to your presentation by simply copying and pasting them or, if you are applying a pattern, copying and pasting the selected graphic style. You can also adjust the tint, brightness, and other parameters of the frames and characters, as well as change the fill and opacity of the patterns.
Decor Graphics is designed to be used with Apple's Keynote, but you can also paste the images to Pages, Numbers, or iBooks Author.