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.
hash hush hatch heishi heuch hitch hooch hotch hutch
ash mash deash fash hash cash gash quash lash bash leash gnash pash rash sash dash wash sh