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.
sheets sheds shuts shits shots cheetahs shotes shades shutes shouts shoots shoats cheats shotts shiatsu chetahs shittahs shoddies chats chits shads chotts shadows shiatzu
beets sheets weets leets keets deets meets pets needs wheats netts bootees cheats redes seeds goatees lets rets fetus diets etas tees suets meats tutees feeds yetis aedes suttees jets gets hets fetes fets metis fetas quiets feats deeds teats cetes vets haets poets settees pedes cedes sets heats reeds nets pietas bets jetes zetas suedes newts foetus neats coatees puttees peats quietus seats meeds betas getas heeds eats setts beats dees duets tets weeds wets whets metes yetts
sheet cheetah shed shied shoed ashed