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.
regret regreet regrate regrade recreate regard recrate recruit recurred required recarried record
aigret egret regret grot skirret grit secret cigaret regreet bogart great greet grat garret curet cruet caret secrete yogurt