While the app allows us to filter/search our library (why can't we do this on the website?) it would be useful to be able to bulk add items to collections instead of having to add them one at a time from the item page itself.

Couple ideas of how to implement:

1. From the main library listings, the ability to multi-select via a check box (or other multi select mode) with a "add to collection..." button to select what collection to add it to.

2. From the collection itself, have an "add items to collection" button that you can search/filter the items in your library and click check boxes (or just the item itself) to select and a button to add all selected to the current collection.