The Silverlight 5 Toolkit theming core package. You must add specific theme assemblies separately. Packaged by Singulink (www.singulink.com) as apparently no more love is being shown by Microsoft for Silverlight :(
Ljund Controls contains Windows 8 themeing for WPF and helpers for animation of controls such as fading in/out, resizing, sliding and more.
In addition to these core features, a TextEntryDialog is provided, and a helper for navigation between pages in a WPF Frame.