There I was, attempting to add a collection to my scene from another file. After attempting to link to it (File > Link), nothing would happen. It took me a little while to figure out that it wasn’t inserting it because it was already imported. At first, I would hunt around my scene trying to find the already-imported instance to duplicate for use elsewhere, which just seemed abusrd. After thinking on it a little, I realized that you can just open the file outliner, find the collection, right click on the collection, then click on ‘Instance to Scene’, and it will insert it at the 3d cursor location.
Personally I would prefer if it still just create another instance of the collection instead of just staring at me blankly. Usually I’m not entirely sure if I’ve already imported the collection, so I waste a little more of my time trying to import it, and then have to dig through the outliner to add in another instance.