For accordions, my experience is there are 5-7 rows (each manufacturer varies) per column. The first row is actually the minor 6th (a 3rd below) the second row, which is the note the column is based on.

The following rows in the column are usually a minor, major, minute 7th, major 7th, then sometimes augmented or diminished or MM7.

The root note on the 2nd row is arranged in a circle of 5ths, usually the middle corresponds to middle C (denoted by an indentation)

This is my experience with the LHS of piano keyboards.