Has an AFL game ever ended 126-55?
Exactly once. On June 9, 2018, Sydney beat St Kilda 126-55, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 126-55 in league history.
That makes 126-55 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 127-55 has happened 4 times and 126-56 has happened never.