PixiEditor

Likely the most customizable and advanced color picker for WPF and AvaloniaUI.

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Usage guide

Select your framework

Install the Package

$ dotnet add PixiEditor.ColorPicker --verison 3.4.2

Use the component 

<Window
    ...
    xmlns:colorpicker="clr-namespace:ColorPicker;assembly=ColorPicker" 
    ...>
    <colorpicker:StandardColorPicker x:Name="main" /> 
    <colorpicker:PortableColorPicker ColorState="{Binding ElementName=main, Path=ColorState, Mode=TwoWay}" />

Read further documentation

Visit the docs