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.
nitro niter nitre nitery nittier niterie knitter noter nadir nutter netter notary nature natter neater nutria neuter knotter nattier needier nettier nuttier gnattier knottier
nitro baiter citer retro biter niter loiter miter toro liter trio trow troy tyro titer suiter waiter strow tiro hetero kiter writer outrow nitre mitre litre metro guitar goitre taro goiter gaiter cuatro suitor stroy titre sitar whiter
nit knit nite nitty snit unit unite unity