Flight Global has a fascinating article on the number of planes parked in the desert by type. Using a percentage of the total active fleet for each type, the list is both depressing and fascinating. 

Definitely read the article but the tl;dr list goes like this:

  1. Boeing 737 classic
  2. Bombardier CRJ
  3. McDonnel-Douglas MD-80
  4. Boeing 757
  5. Airbus A320
  6. Embraer ERJ-145
  7. Boeing 767
  8. Boeing 747 Freighter
  9. Boeing 737NG
  10. Boeing 737-200