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.
guarder garter carder grader curdier quarter grodier gridder greedier quartier garroter garotter cruder corder grater carter curter greeter grouter gritter crowder greater courter courtier cruddier grittier grottier groutier carrotier crater krater critter curator
harder carder guarder warder yarder larder boarder hoarder ardor pearter arider charter forrader garter hardier cruder marauder corder readier ruder carter herder border joyrider birder broader nerdier rider braider derider weirder lardier parader girder reader barter quarter lowrider grader order sardar tarter treader torrider curdier murder raider reorder darter tardier tireder trader horrider wordier
guard garda gardai gourd gourde