Ship a Full HTML Editor Without Building One
In production since 2007, ready for .NET 11. Available through one NuGet install, with an optional source code license.
Drop the control onto a form and your app gains a complete HTML composition surface: toolbar, WYSIWYG editing, formatted source view, spell checking, tables, images, and dialogs - the plumbing a team otherwise spends weeks building before the first real feature ships.
SpiceLogic has shipped this control since 2007, and the current line is rebuilt for modern .NET - so a maintained WinForms application gets professional HTML editing without turning the editor into a side project.