You can earn Cards in Little Alchemist Remastered in a few different ways.
The simplest way to get more cards is by buying Packs from the Shop. Packs are available for purchase with either Coins or Gems. Whenever you defeat a Boss in Adventure mode, there is a chance that they will drop a card from their Prize Pool. Reaching certain Levels through earning Experience will reward a Card. Your Cauldron Reward for reaching a seven-day streak will be a free Card Pack.