They're the new reward cards being given out on the daily quests as a rewards of sort for playing the game. The number of cards you receive is based on the league you're currently placed in. The new reward system does require players to now have a good balance of splinters in order to earn with the daily quests. I'm really impressed with how the SM team come up with ways to combat game abuse and trying to build a game that is enjoyable for everyone, from the smallest to the biggest investors.
Link:
https://steemit.com/steemmonsters/@steemmonsters/new-reward-edition-cards