Previously in MTG Online was possible to build decks with cards not present in your collection. This is not possible any more in the latest MTG Online client.
Can someone advice on how I can build a deck with cards which I do not own, pls?
When viewing your collection, click the quantity button and then move the left slider to 0 to show cards you don't own. Once you see them you can just doubleclick them to add them to your deck.