[zzo38computer]

There are other five bit character sets as well, such as the 5-bit Baudot character set and the 5-bit Zork character set. You could also use variable bits characters, or other bases of numbers.

You can also use other decks, e.g. with tarot cards you will have 78 cards rather than only 52 cards, and can make a longer message.

Other comments on here had mention doing other things such as face-up vs face-down cards.