monogame-forms
There are 2 repositories under monogame-forms topic.
BlizzCrafter/MonoGame.Forms
MonoGame.Forms is the easiest way of integrating a MonoGame render window into your Windows Forms project. It should make your life much easier, when you want to create your own editor environment.
BlizzCrafter/MonoGame.RuntimeBuilder
The MonoGame.RuntimeBuilder builds your raw content asynchronously to the .XNB format during runtime.