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.
tennist tinniest teeniest tanist tiniest toniest tensity tannest tawniest tenacity tensed density dunnest downiest tonicity dynast dynasty
tennist boniest mooniest bonniest fawniest looniest finniest funnest fenniest tannest tiniest dunnest teeniest toniest zaniest wannest runniest wenniest punniest whinniest piniest sheeniest hymnist neist phoniest downiest monist gooniest canniest liniest ginniest viniest hygienist tanist funniest tawniest veiniest tinniest sunniest waniest rainiest weeniest puniest whiniest pianist winiest luniest shiniest
tennies tennis taenias tenias tenuis tunnies