Bonus Cards are an important part of Monster Crew, adding a lot of depth and strategy to the game. They can be helpful in all sorts of different ways, giving you more Loot, more Health, turning your enemies into edibles, and a lot more. You gain some Bonus Cards for free just by progressing through the story in Monster Crew, while additional Cards can be purchased and upgraded for Coins and Monster Tokens that you collect while playing. Cards can be used once during your run, but are yours to keep once you have acquired them, so you can use them whenever you play a game.
We have put together a new Bonus Card page here on our website that we hope will help you to plan your strategy when deciding which card to get or upgrade next.