3 aircraft and 5 cabin layouts, from the 737-700 to the 737-800. Pick one for its seat map, the best seats and the seats to avoid.
There are seat maps for 3 Southwest aircraft here: the Boeing 737 MAX 8, the Boeing 737-700 and the Boeing 737-800.
The Boeing 737 MAX 8, with 175 seats: 175 Economy in its main layout.
The Boeing 737 MAX 8, with 32" of seat pitch in Economy and seats 17" wide.