Any easy tool to cherry pick rare words from text for vocabulary building?

Seems the most straightforward thing to do would be to list every single word from the text according to its overall English rank, perhaps with some cutoff point to keep the list length down. Somehow, my google fu is failing me, but surely such a simple tool already exists somewhere. This would spare me from having to write down every word I don't recognize as I read a text--I could just take a glance at the list and see all …

building easy languagetechnology text tool words