Common cards are the weakest and most easily obtainable card in the game. They are among the first group of cards players will encounter, and are signified by having one star in the lower left hand corner. Despite their namesake, common cards are actually the second most abundant type of card in the game, with Rare cards being the most abundant.
Common cards tend to be relatively weak in comparison to Rare and Ultra Rare cards in terms of stats. They generally have a low rate of increase in stats as they level up. As well, their regular forms can only be enhanced to a maximum level of 20, and a maximum level of 30 for their EX versions. As such, they have a lower strength potential than their rarer counterparts, and are generally most useful for enhancing Rare and Ultra Rares.
Like all cards, they can be sold for Coins.
Common cards can be acquired through a variety ways. They are often awarded for progressing through quests, events, and through trade with other players. Because of their abundance in-game, they can often be acquired in a trade relatively easily for coins.
They can also be acquired by drawing from the Friendship Card Pack, in exchange for Friendship Points. As well, one free card from the pack is awarded to the player daily.