Has an AFL game ever ended 73-18?
Exactly once. On May 13, 1899, Sydney beat Carlton 73-18, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 73-18 in league history.
That makes 73-18 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 74-18 has happened never and 73-19 has happened never.