A challenge set requires users to collect specific card editions to make up a particular set of cards. Those cards and editions can be browsed by the user within the Discovery Tab. Some challenges will only be unlocked when the user reaches a certain level. These challenges will have higher rewards to provide further motivation for levelling up. Users can be required to collect 3,5, or 7 editions across a range of celebrities to complete a set. Some challenges will be predetermined. Others will be created on an as-and-when basis. Also, each celebrity will have a catalogue of challenge sets that users can complete to earn a reward.