Other contributors have said "Can you name twenty different breeds of dog from smallest to biggest?" is the same question as "Which breeds-of-dog are the biggest and smallest?" If you believe that these are not asking the same thing and should be answered differently, click here
The tallest breed of dog is the German Great Dane. However, the heaviest breed is the Swiss St. Bernard. The smallest dog ever is the Chihuahua from Mexico. It is also the lightest breed of dog.
Depends on the dog not the breed I think. The Chihuahua and Pomeranian sorta tie for first. Like I said, depends the dog. The Chihuahua could be second or the Pomeranian.
That depends what is meant by "biggest". If you are referring to girth, the English mastiff can be up to 44 in. tall and weigh more than 200 pounds although some unhealthy fat ones can weigh over 300...