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.
ferrets frets ferrites ferrates fretsaw forts ferities verts frats farts frits fruits vertus fritts fortis veritas verites verities foredoes fords fritz varieties fards farads fiords fortes frauds frites virtus fordoes forties
barrets turrets terrets ferrets garrets rets aretes berets greats treats frets carets pierrots parrots carrots greets keiretsu curets territs cruets trets burets worrits
ferret ferrety feared ferrate ferried ferrite furred