Top 20 NuGet XAML Packages

Style XamarinForms-apps with Css
Provides infrastructure helpers and services to ease WPF applications development.
Colorful.Console adapter of Alba.CsConsoleFormat. Supports rendering FIGlet fonts.
Library for advanced formatting of console/terminal output. Format output like HTML using either .NET DSL (like LINQ to XML), or XAML with bindings (like WPF). Supports paragraphs, lists, grids, Unicode formatting, drawing, export to various formats and much more.
Markdown XAML processor
ResourceDictionary instances containing Material Design templates and styles for WPF controls in the MahApps library.
A rich library of helpers, services, and base classes for new and existing Windows UWP apps to maximize awesomeness and minimize boilerplate garbage. This library has a companion Visual Studio Extension called "Template 10 Template Pack".
WPF Light UI Toolkit
This package provides backward-compatible versions of Windows UI features including UWP XAML controls, and Fluent styles and materials. It is part of the Windows UI Library.
Core XAML Components: View Models, Converters, etc.
Yet Another (UWP XAML) Chart Component (yacc). See the wiki on Github for more info.
A winmd package that add navigation in SplitView
A simple library to display animated GIF images in XAML applications. Supported platforms: WPF (4.0 and later) UWP (Windows 10), Windows 8.1, Windows Phone 8.1, Silverlight 5.
System.Waf is a lightweight framework that helps you to create well-structured XAML applications. This is the portable core part that can be used in different application types.
This package provides a standard way for middleware authors to use XamlDirect APIs on earlier versions of Windows 10 without needing to write special code to handle multiple target Windows 10 versions. It is part of the Windows UI Library.
Xamarin Forms effects library.
Build tools used for building extensions to the Visual Studio project system.
Easily add interactivity to your Avalonia apps using XAML Behaviors. Behaviors encapsulate reusable functionalities for elements that can be easily added to your XAML without the need for more imperative code.
Markup class in WPF Xaml, converter is main.
This package is only a redirect to the System.Waf.Wpf package. System.Waf.Wpf is the successor of this package.