Has an AFL game ever ended 66-42?
Exactly once. On September 8, 1906, Geelong beat Essendon 66-42, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 66-42 in league history.
That makes 66-42 the 3884th most common final score out of 6,649 that have ever occurred in AFL. One point away, 67-42 has happened 1 times and 66-43 has happened 3 times.