Feenie
the letter a represents the o sound when it follows w ... most of the time (in 19 words) More than 19, surely.
I could find only
Swallow, swamp, swan, swap;
waft, wand, wander, want, wanton, warrant, warren, warrior,
was, wash, wasp, watch, watt, wattle,
what.
There are also 10 with 'qua'
Quality, quadrangle, quantity,
quarantine, quarry;
squabble, squad,
squander, squash,
squat.
The nastiest 4 alternative spellings for are:
Cough, trough;
laurel, sausage