DarkUI is an open source library that helps you design an awesome UI for Windows Forms Application.
Creating a new Windows Forms Application project, then right-click on your project => select Manage Nuget Packages => Search DarkUI => Install.
After installing the DarkUI library, you need to rebuild your project. You will see the DarkUI control automatically added to the Visual Studio Toolbox.
If you don't see the DarkUI control in your Visual Studio Toolbox, you can download the DarkUI from GitHub: Link
Next, Right-click on your Visual Studio Toolbox, then select Add Tab => Enter your Tab name.
After creating your tab, you can right click on your tab =>Choose Items
You will see Choose Toolbox Items dialog => Select the .NET Framework Components tab, you can click Browse button, then select DarkUI.dll
Now, you can drag some controls to your winform.
And don't forget to change the inheritance from Form to DarkForm.
public partial class Form1 : DarkForm
As you can see, DarkUI control also supports many basic libraries for Windows Forms Application.