Google Word Frequency Counts
From MallWiki
Below are the ~38000 words with the highest frequencies in the Google corpus. This represents all of the tokens that appear with a frequency of greater than one in a million. The corpus size is 1024908267229, that is over a trillion words. So even words that appear once in a million tokens have been seen over a million times, so estimates should be very tight. Hopefully, this will make selection artifacts largely a thing of the past (at least as far as frequency is concerned). Note tokens with different capitalization have been combined in the list below.
The full count list. Note this version keeps tokens with different case variations separate.
