Shark Card

• The shark card can be used to pick one player at random who will get four cards. Being that you need to discard all of your cards to end the hand, this sets a player back.
  
  

Spy Card

• The spy card can be used to hide how many cards you have from other players. This can be useful as players are required to say "Uno" to warn other players when they are down to one card.
  
  

Which Version?

• The Shark and Spy cards are only available on the electronic versions of Uno available on the Internet. There have been many Uno spinoff versions which include special cards for the particular theme such as the "Pirates of the Carribean Uno" with the Black Pearl card.
  
  

Uno Basic Cards

• The basic cards in an Uno pack are the number cards, from 0 to 9, in four different colors. There are also three action cards in each color labeled "skip," "draw two," and "reverse," enabling the player to affect the passage of play. Black action cards of named "Wild" and "Wild Draw Four" are also included. there are 108 cards in a traditional Uno set.