MaterialDesignColors — nugetz

Install-Package MaterialDesignThemes

<Application 
  x:Class="Example.App"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
  StartupUri="MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <materialDesign:BundledTheme BaseTheme="Light" PrimaryColor="DeepPurple" SecondaryColor="Lime" />

                <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesign2.Defaults.xaml" /> 
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

<Window [...]
  Style="{StaticResource MaterialDesignWindow}"
  [...] >