Has an AFL game ever ended 81-21?
Exactly once. On July 4, 1964, Hawthorn beat Footscray 81-21, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 81-21 in league history.
That makes 81-21 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 82-21 has happened never and 81-22 has happened 1 times.