During gameplay, there are a number of Boosters available to help with clearing the Tableau.  These can be seen at the bottom of the display:
  • Extra Card - adds 5 Cards to the reserve.
  • Undo - reverses the previous move.
  • Wildcard - allows any available Card from the tableau to be matched.
These Boosters can be activated by spending Coins; the amount will be displayed with their icon.  Alternatively, these can be earned as rewards from various sources in the game and stored in the inventory; the number of each available is also displayed with their icon.