I’ve been searching for this feature and it doesn’t seem to exist or have been requested, so I’m creating it. I understand it may be not super interesting but it always helps to avoid this little repetitive tasks that perhaps are easy to automate.
My main task is to create banner ads and almost every network always requires 1 px border in every banner. So I create the border by hand. I wish there was an option to export the materials with a border automatically. Or maybe, a new kind of object “Border” that is a rectangle with no fill and customizable color and width that expands to the scene edges automatically.