Phrases Sayings And Idioms

1200 phrases and sayings and their origins!  They also have fun categories, like fallacies (misattributed quotes, etc.)

Sayings and Phrases - meanings and origins

Of course, I have 3 books on the subject I haven’t read yet:

101 American English Proverbs
Random House Dictionary Of America’s Popular Proverbs and Sayings
Rawson’s Dictionary of Euphemisms and other Doubletalk