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.
stiffer staffer stuffer stuffier stiver stuiver stover
stiffer differ stuffier daffier deffer deifier doffer duffer beautifier codifier edifier modifier notifier ratifier rotifer staffer stuffer titfer
stiff stiffie staff stuff stuffy