Imagine you wanted to study vocabulary in advance of reading not just a work, but an entire corpus, or perhaps the super-corpus of the Greek Classics. Wilfred Major advocated for learning a core vocabulary in his paper It's Not the Size, It's the Frequency. In it he provides some good news:
Ancient Greek has a high-frequency core vocabulary scarcely half the size of many other languages.
He provides lists of lemmata which comprise 50% or 80% of the words in the ancient Greek corpus. The 80% has only 1,100 entries, so it is definitely achievable for advanced students.
I have made a flashcard pack at Quisition which contains this vocab list. If you think it would be useful to your studies, you can add it to a deck and start memorizing.