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.
grassier greasier gorsier grosser grazier crasser greaser cuirassier creasier grazer creaser grouser crazier crosser crosier caresser crosshair curser grocer cruiser crozier courser coarser grocery corsair carouser curiouser crozer cursor
brassier drossier tressier prissier grassier dressier cuirassier pursier harasser grosser brasier rosier crosier drowsier presser gorsier caresser brassiere crosser creasier frowsier crasser prosier horsier dresser greasier reissuer tarsier trusser
grass grassy crass grays grease greasy gross