I've taken a list of English words, and examined each of them to see what they sound like (using the PHP metaphone function). This page lists the most common metaphone codes, along with their words. You can also search for a word of your own, and see which words sound similar - and which ones rhyme, and which ones alliterate.
spotter spottier spatter spitter spouter sputter sputtery scepter spader spider sceptre speeder spidery spudder septaria speedier
potter spotter sputtery spouter spottier spitter spatter copter puttier putter powter pouter pottier pottery pettier petter patter sputter diopter
spotty spot sapota sapote spout