SplinterGlossary: Cards Airdrops
A reward system based on airdropping a certain card at regular milestones of packs being sold on the primary market was introduced.
For the Untamed edition, the milestones were every 100,000 packs sold. At a total supply of 1.5 million, there were 15 airdropped cards then.
For Chaos Legion, the milestones are every million packs sold and there are 15mil packs for sale. The airdrop rules changed a bit because there was a presale and a general sale, and for the first 2mil there was only one card airdrop, Doctor Blight, but otherwise the system was the same.
Dice mini-set had a similar system too.
To attempt to receive such airdrops, someone needs to buy packs from the primary market (NOT from the secondary market - if packs are purchased from the secondary market, any potential airdrops go to the initial purchaser from the primary market).
Chances increase with every pack purchased and the earlier they are bought because they participate in all airdrops from the moment of purchase onward. From a number of packs purchased upward an airdrop is guaranteed, otherwise, it's just potential.
Rules of these airdrops may vary slightly or be completely changed in the future. No one knows exactly what they will look like until the official announcement comes.