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.
groks grogs croaks gregos crocks crooks karaokes carks kirks crocs corks grigs crakes quarks creaks creeks crucks cricks cracks cargos crocus quirks cargoes croquis caracks cariocas carracks curacaos curacoas garigues
groks taroks croaks tarocs arks irks lurks largos marks burkes grogs karaokes narcos mirks pargos carks brocks porks trokes crocs sorgos shirks darks chirks charkas sargos frocks forks trocks warks frogs jerks dorks drouks brooks treks burkas parks quarks kirks crocks perks corks parkas murks crooks cargos trogs borks merks larks markas irokos progs quirks rocs narks durocs turks rocks birks berks barks sarks dreks troaks araks dirks zerks rooks works charks harks sharks yerks