How would you go about showing an editor preferences panel in the inspector?

I’d like to do this without using a gameobject. What I’m trying to accomplish is something similar to how the Settings menus work, where you select an option from the toolbar, ( Edit > Project Settings > Editor, etc) and clicking one shows that menu in the inspector.

You can create a ScriptableObject with a custom inspector and then change the current Selection to that ScriptableObject.