The difficulty here may be as in our old friend John Barleycorn. A handful of corn, a sack, a row, a stand, a sheaf, a garner. Depends on situation. A singer may present a sequence of ballads. Several singers would bring us a succession. In a book a collection.
A murder of crows describes them wherever they are, as does a charm of finches.
I like 'garner' as in 'Garners Gay'...