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.
soaps sops saps soups hyssops zaps sips spas sups sipes supes spaes spews spays spies spues seeps speise speiss spouse sepias sepoys suppose seapiece ceps spaz zeps zips
soaps ops poops coups mopes gaps leaps coops goops haps roups cops rapes papas fops kops laps baps napas naps apes apos knaps lopes oops soups whoops yaups shops daps chops cheapos pops chapes woops tapes whaps apse reaps topis tops capos taps hyssops dopes biopsy bops apps loops copes saps knops jaups sops mops gawps ropes kapas maps lapse loups capes opes hoops caps lapis gapes wraps copse opus napes lops neaps heaps zaps paps raps popsy tapas hops topes popes waps topos hopes whaups whops tapis wops chaps japes cheaps shapes dopas yaps yawps
soap soapy sap sop sappy soppy soup soupy