A
rhyming dictionary is a handy tool for
songwriters and
poets that lists a lot of
words by their
ending.
For instance, to find words that rhymed with "Foo," you would flip to the section that listed "OO," and you'd find Goo, Blue, New, and dozens of other words.
I'm sure that you can obtain one from one of the many online booksellers, or use an online one like http://www.writeexpress.com/online2.html