Here is a huge list of Cheng Yu that chinese people should have learned in elementary school. And on a real note, these should cover all the cheng yu that are worth learning. Higher level Cheng Yu may be nice but not entirely practical. The only time they might need it is if they're tested on it, but that's about it. The majority of these cheng yu are recognized by pleco's built-in dictionary. I got all of these from this site, http://cy.5156edu.com/page/z8308m7738j20074.html .