According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 12 words with the pattern -AX-S. That is, five letter words with 2nd letter A and 3rd letter X and 5th letter S. In alphabetical order, they are:
faxes
laxes
maxes
maxis
paxes
raxes
saxes
taxes
taxis
taxus
waxes
zaxes