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.
subset subside subsite subsidy subacid
subset basset bassett bast beset best bust fabbest vibist cubist robust tubist
subs subsea sabs sibs sobs soubise subahs subas subbase subbass