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.
nature nitre natter neater nattier niterie gnattier noter nitro niter nuder nadir nitery nutter netter neuter notary kneader knitter knotter nettier nittier nuttier knottier
feature future mature couture suture nature stare tare tire outre auteur retore trey stourie hauteur store stoure strew stere tyre titre tree stour dure satire attire nitre quatre mitre true litre tore datura faitour metre goitre tour retire detour shoetree
gnat gnatty natty neat anatto enate