You can collect cards in the game in several different ways. They are collectable items. 9 cards make one collection. If you complete one collection you will get cool rewards in form of spins, coins or pets. If the card collection is rare you will get even better rewards in return. It is definitely worth it to collect cards.
Every level got specific cards. It depends on your village level which card you can find. You will also find cards in chests.
- Wooden chests: 2 cards
- Golden chests: 4 cards
- Magical chests: 8 cards
One common practice is to trade cards with your friends, when you need one to complete a collection.
There also gold cards, which you can find when you are on a higher village level.