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.
sieur sir ser sierra sire suer sere sure sera seer sour sear sura siree surra surah serow sirra serry saury surrey zooier sirree soiree sirrah sri sori sore cere soar sari cire cero zero sora
sieur bier euro feuar fiery vier gooier kier queuer lier pier wrier zooier doughier tier shier