Multiplier Cards are what you want to see when you need mucho points.

There are two types of Multiplier Cards. 2x cards have a pink stripe, and double your score for any valid word that contains the 2x card. This is on top of the normal multiplier for word length.

3x cards have a blue stripe, and triples your score for any valid word, on top of the normal word length multiplier.

You can also combine Multiplier Cards in a single word for really astronomical scores. For example, if you had two 2x cards and one 3x cards in a single word, it would multiply the value of that word by 7x (2 + 2 + 3).