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.
riposte ripost ripest reposit reposed reopposed rapist repast ropiest rapeseed repassed roupiest
riposte post deposed ripost reposit reposed reopposed opposite opposed apposite apposed postie posit posed piste paste supposed deposit pst
rips repos repose ripes ripsaw grips drips tripos trips