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.
outsat outset outsit outsaid outstay outcity outside
outsat phattest whitest wettest tautest detest pietist outset neatest lutist latest quietist quietest cutest coattest disseat fittest test featest fattest autist attest tost mutest hottest outsit retest duettist wattest whatsit chutist
outs outsaw outsay outsee oats oots ouds