Click the link below for a variety of lesson plans for each grade level. Many of these include artist studies, etc. so feel free to cut out what you don't want and keep what you do in the lessons. You can modify any of these to your liking.
There are art binders in the art cabinet on the far right by the wall in center court, on the top shelf. The binders go by grade and are filled with lesson plans. Feel free to look through them and see if anything is to your liking! Under that shelf, on the right side, is an open topped box filled with large brown file folders one per grade. In each one is sample art for lessons from the binders if you would like to use one as an example.