Consider potentially useful, open source controls

[PawelTroka]

useful controls: https://github.com/AdamsLair/winforms https://www.nuget.org/packages/OpenTK.GLControl https://github.com/nathanchere/FerretLib.WinForms http://ascendnet.codeplex.com https://github.com/AdamsLair/winforms