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.
knits nits knots nites knouts nuts nets neats nidus nides newts notes nates gnats netts nowts nutsy kneads naiads nudies naiades neddies noddies nods
knits nits its boites aits bitts bites fits bitsy baits pitas gites litas quits kits rites bits mites writs sites situs suits zits ditas dits doits titis toits whites wites chits raitas fiats gits pits tits waits ditsy duits diets dites suites zitis cites sits riots writes gaits wits whits hits nuts nets coitus nites knots gnats mitts mitis lits quoits quiets kites shits
knit nit knot knotty nite nitty kent kente snit unit unite unity