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.
higher huffier haver hover havior heaver heifer hoofer hoover haviour heavier
higher cougher laugher nigher rougher sigher tougher weigher gopher cipher cypher sphere sphery sypher