I thought of an idea to add to filters to collections...
For example, you want a collection that includes only certain ar/od/star beatmaps etc, you would apply the filters to a collection and you have a neatly organised collection, you wouldn't need to search for the beatmaps that match these filters every time you want to find them. Also you wouldn't need to constantly update the beatmaps in the collection because it would update itself on its own everytime you download a new beatmap.
For example, you want a collection that includes only certain ar/od/star beatmaps etc, you would apply the filters to a collection and you have a neatly organised collection, you wouldn't need to search for the beatmaps that match these filters every time you want to find them. Also you wouldn't need to constantly update the beatmaps in the collection because it would update itself on its own everytime you download a new beatmap.