List of buildings most in need of being drawn
 

This diagram lists the tallest highrise buildings in the SkyscraperPage database which do not have a drawing - http://skyscraperpage.com/diagrams/?searchID=107 (only diagram members can access the page)

You can also search for more structures by changing the Structure Type and Status values on the search form. It is also possible to narrow the list by city or country by using the search form. This way you can find a building to draw which may interest you.