Near rhymes (words that share some but not all sounds):
* father
* smother
* gather
* laughter
* after
Eye rhymes (words that are spelled similarly but pronounced differently):
* charter
* altar
* smarter
Near rhymes with a slight twist:
* further (though this is a synonym rather than a strict rhyme)
* warter (a humorous made-up word, but it rhymes!)
Ultimately, the best rhyme depends on the context and the effect you want to achieve.