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.
umbral umbrella
timbral umbral morale demurral numeral nombril memorial gomeral gambrel moral cameral humoral timbrel fimbrial femoral amoral mural immoral tumbrel tumoral humeral tumbril whimbrel