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.
casus caseous casas cases cassis causes cassias causeys caseose gaseous casease coses gases coseys cosies cusses cussos gasses cuisses gausses quasses quassias
casus biases leases cases gases vases phasis issues feases eases reissues phases peases risus pases ceases oases teases misuse wiseass masas sass basis suss missus lusus byssus lases sous sues casas baases bases sassy reseaus rases rousseaus passus disuse oasis tissues nisus chases
casa case cassia cause causey caws cays caucus ocas