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.
whitier whiter wittier whitter waiter whetter wider wheatear water wetter watery watter widder weedier woodier wader wadder wedder weeder
mitier pitier whitier tier zootier tattier hootier quitter cottier fitter rattier matier poutier ruttier ritter sootier citer dottier cattier haughtier waiter goiter hitter litter baiter knitter nattier niter nittier peatier guttier jettier miter wittier chitter jitter metier gnattier loiter titer nettier bittier kiter goutier gaiter biter battier meatier pettier bitter liter footier knottier nitery nuttier dotier chattier whitter whiter titter tidier doughtier suiter fattier sitter writer rootier rioter puttier pottier shittier