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.
woofer wafer wafery whiffer whoever waver wiver waiver wavery wavier weaver weever weigher
gofer roofer hoofer woofer fer offer knifer miffier loafer liefer cover goffer feoffer fere fear puffier puffery reefer huffier niffer duffer over defier shofar quaffer safer suffer daffier defer buffier mover differ wafery piaffer chaffer chaufer chauffeur chuffer iffier beefier lover reefier coffer lifer gaffer refer hoover rifer goofier heifer hover leafier reifier reoffer puffer gauffer coiffeur buffer fifer rover sofar zaffer deafer deffer deifier doffer wafer whiffer chafer chaffier chauffer chiefer chuffier shover