Rui Santos @ randomnerdtutorials.com has compiled a list of 25 useful Arduino Shields that you might want to use on your next projects. The list includes Ethernet shield, Relay, Motor, LCD and many more.
Arduino shields are boards that will expand the functionalities of your Arduino. You just need to plug them over the top of the Arduino board. There are countless types of shields to do countless tasks.
25 Useful Arduino Shields That You Might Need to Get – [Link]