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.
sera serai ser sierra seer sear suer sura sere sora ceria sirra surra sieur surah serow serry sirrah sir sri cero soar cere sore sari sire sori sure sour zero saree saury siree sorry