This system could work similar to how the current (object) variable system works (see picture below). If I click on an object, I can navigate to its behaviors / effects, copy one (or multiple), and paste them in another objects list.
Here is the current variable system:
Something like this for behaviors and effects would be handy.
Why add this? Well adding effects and behaviors to many objects can be tedious, and as far as I know, there are no shortcuts. In one example of mine, I have many objects that I created a while a go and need to add effects to them, so I can’t create one object and copy/paste it with its effect.