Has an AFL game ever ended 78-16?
Exactly once. On August 27, 1898, Geelong beat Melbourne 78-16, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 78-16 in league history.
That makes 78-16 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 79-16 has happened never and 78-17 has happened 1 times.