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.
mommy mummy mammy momma mom mammey mumm mome momi mamey mamma mammae mammie mammee mem mim mum maim mama meme memo mime mumu
commy mommy pommy tommy shimmy chummy womby jimmy tummy comma jammy tammy boomy doomy immy roomy gammy loamy dummy rammy gemmy homey shammy chammy whammy rummy foamy gummy hammy jemmy mummy mammy homy momma mammey emmy yummy
mommy momma mom pommy pommee comma commie commy mamma mammae mammee mammey mome momi mumm mummy mammie pommie mammy tommy