The tallest is the Irish wolfhound ( 30 - 37 inches ) then Scottish deerhound ( 28 - 35 inches ) then the Limburger ( 29 - 34 1/2 inches ) then the great Dane ( 28 - 32 inches, although some can reach 36 inches ). The smartest is the border collie then poodle then German shepherd then golden retriever then doberman pinscher. The heaviest is the English mastiff weighing in at 170 - 250 pounds, then the st Bernard weighing 160 - 220 pounds. The strongest is the dogo argentino ( Bred to hunt jaguars, pumas and other large dangerous aggressive game ) 24 - 28 inches and 80 - 130 pounds )
Then the American bulldog ( They have the weight pulling record of 11, 300 pounds or something close ) 22 - 28 inches and 70 - 140 pounds.
Then bullmastiff ( Bred to out power and overpower a human no matter how big strong or heavy the person is ) 24 - 29 inches with 28 proffered, and 90 - 140 pounds.
Then English mastiff, bred to do the same as bullmastiff and also fight lions, bears, tigers, humans, and wolfs. 28 - 36 inches, and 170 - 250 pounds.
I breed own and sometimes show purebred rottweilers, border collies, american bulldogs, english mastiffs, bullmastiffs, boxers, and dogo argentinos.