2 aircraft and 2 cabin layouts, from the 42-600 to the 72-600. Pick one for its seat map, the best seats and the seats to avoid.
There are seat maps for 2 Alliance Air aircraft here: the ATR 42-600 and the ATR 72-600.
The ATR 72-600, with 70 seats: 70 Economy in its main layout.
The ATR 42-600, with 30" of seat pitch in Economy and seats 18" wide.