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.
pianist piniest puniest punniest pancetta hyponasty
pianist tanist zaniest sunniest downiest ginniest hygienist canniest punniest gainst canst neist gooniest meanest mooniest piniest tawniest tennist tinniest waniest wenniest whinniest sheeniest liniest luniest runniest hymnist phoniest boniest funniest finniest fenniest fawniest leanest bonniest sanest looniest monist veiniest puniest rainiest viniest teeniest tiniest toniest weeniest whiniest winiest shiniest