Has an AFL game ever ended 100-55?
Exactly once. On September 8, 1923, Sydney beat Richmond 100-55, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 100-55 in league history.
That makes 100-55 the 3884th most common final score out of 6,649 that have ever occurred in AFL. One point away, 101-55 has happened 3 times and 100-56 has happened 5 times.