There was a discussion on this board some time back of where to find a word frequency list for classical Greek: http://discourse.textkit.com/t/frequency-list/4778/1
In case it’s of interest, I’ve made a frequency list for classical Latin: https://github.com/bcrowell/ransom/blob/master/lemmas/classical_latin_freq.json It’s a human-readable and machine-readable file in which each dictionary lemma is listed along with the number of occurrences in the corpus I used, which I drew from Project Perseus’s treebase. The authors are the following: Caesar, Cicero, Ovid, Petronius, Tacitus, Vergil. I picked them basically by looking at the Wikipedia article https://en.wikipedia.org/wiki/Classical_Latin and picking out authors who had been analyzed in the treebase, and were so famous that even someone as ignorant as I am recognized them. I also added Petronius simply because I was using a story of his as a test for my software. Since the portion of the Satyricon they analyzed is pretty long, this also helps to bulk up the sample size and get some lower-frequency words on the list. For most of these authors, Perseus hasn’t actually analyzed everything that person wrote, just certain selections, so my corpus isn’t actually super huge.
If anyone is particularly interested in having such a list constructed for some other period of Greek or Latin, let me know. It’s easy for me to do if you can define a corpus for me by listing some authors who are in the Perseus treebank. Lists of authors they’ve analyzed are here:
Latin: https://github.com/PerseusDL/treebank_data/tree/master/v2.1/Latin
Greek: https://github.com/PerseusDL/treebank_data/tree/master/v2.1/Greek
This version of Project Perseus is under a CC-BY-SA license, so any frequency lists constructed from it also have to be under the same license.