Has an AFL game ever ended 66-6?
Exactly once. On May 23, 1953, Footscray beat Fitzroy 66-6, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 66-6 in league history.
That makes 66-6 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 67-6 has happened never and 66-7 has happened never.