Much like a wildcard in other games, a Foiler card is a card with a QR code that you scan in order to register it in your collection.
Foil cards exist in each of the different rarities: Common, Rare and Unique. Each Foiler can be applied to a card of the corresponding rarity that has not yet had a Foiler applied to it. Once you use it, the Foiler is spent.
When you spend a Foiler, it will apply to the whole card family. That means you’ll only need to foil a cardname once per rarity!
You’ll be able to trade Foilers over the marketplace, just like other cards.
When a card leaves your collection via the marketplace, the foil status is not transferred. Cardnames with Foilers applied will stay in your collection forever. If you ever reacquire that cardname at that rarity, the Foiler will still be applied!
Foiler cards will also be a part of Organized Play rewards.