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.
nett netty net newt neat nutty natty nitty knotty gnatty nut nit not note nude need node nota gnat knit nowt knot nide nite knead kneed knout neddy needy nudie