Top 20 NuGet xaml Packages

Collection of WPF shape controls
A control suite for some common things a Windows 8.1 XAML application might want to include such as a Flyout, Menu, Rating, Settings Pane, and other controls.
A Custom Content Control for Windows 8 app Settings Charm Flyouts.
A Metro Panning Custom Control
A Metro moving background
Multiple Platforms: GetElementRect, GetVisualChild, GetVisualAncestor, Enum extensions, RelayCommand, PropertyChangedBase Windows 8: Flyout, SettingsContractWrapper, LabeledProgressBar, KeyboardKiller Windows Phone: ReverseAutocompletePopup, StatusBarExtensions, CustomMessageBox .NET4.5: CustomMe...
Bob wasn't a great product for Microsoft but maybe Bob can add what's missing for Windows 8
RichTextBlock.Html2Xaml adds a Html property to RichTextBlock controls, that translates Html formatted text on the fly to the subset of XAML that the RichTextBlock control supports, with just two source files that are simple to modify: one C#, one XSLT.
XAML Operations Binding Library
XAML based calendar control for WinRT / Windows Store Style application. Supports full custom styling and comes with a template you can easily customize. Supports all modes, including snapped with the default template.
Part of the Coding4Fun Toolkit for Windows Phone with only the Network library. Items such as a GzipWebClient are in it.
Part of the Coding4Fun Toolkit with only the Storage library. It provides an easy to use wrapper open and save data via serialization.
MVVM Event to Action for your Windows 8 / Windows Phone projects
A simple Date Picker for use in WinRT XAML apps
Calendar control for Windows 10 WinRT/XAML, ported from the Silverlight Toolkit.
A simple and customizable converter/extension from bool to Visibility for Wpf/XAML. It offers a markup extension (so you can use it inline in XAML without defining a resource) and easy custumizability of the conversion.
The "Adornment" helper class provides static wireups for adornments and provides methods for adding ui controls to the adorner layer. <Border> <A:Adornment.Content> <!-- Add adorning content here --> </A:Adornment.Content> </Border>
Windows 8.1 components: RandomColorGenerator, LineCounter, SilentTextBox, TextBlox
Sparked Windows 8.1 Control library