They came with the preorder digital deluxe edition. It was a pack that you can choose one.
Edit: They will possibly release packs later in the game cycle in conquest or something. With the seasons and how they work is different so I don’t really know.
Chances are they'll release them later. But like you stated, since they're Set 1 cards, chances are they won't be released until LATE in the cycle. That is unless they release them before Set 1cards aren't usable for awhile.