For some expansions, it may be important to identify in which language (s) the cards in the collection are
For example :
Extension : "Legends"
Available languages : English / Italian
This could be defined in the "add to collection" popup (one line per language with +/- buttons) and visible when hovering the picture (with the languages flags - with the number of items on it)
The number in the lower left corner of the card retaining its function of aggregating quantities.