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.
typeset typiest typist tippiest deepest dopiest dippiest deposed topside
typeset pest hippiest quippiest lippiest loopiest mopiest nippiest hoppiest ripest seepiest cuppiest soppiest zappiest dopiest deepest peseta nappiest upset whippiest chippiest roupiest hippest heppest ropiest gappiest pipiest happiest pesty pesto loppiest pappiest tippiest goopiest peppiest sappiest soapiest soupiest dippiest zippiest typiest weepiest cheapest choppiest pst