Here are 21 elementary art sub plans that are easy enough to be taught by anyone. Some are full lesson plans; some ideas; some links to good lessons. It is a good reference for both emergency absenses and planned leave.
Here is an easy one-day art lesson with full directions that a sub could do. It is based on a Cezanne still life. The lesson was originally done with watercolor, but certainly could be replicated with crayons or markers. There are both step-by-step directions for the lesson and visuals for every step. There’s not often you find all this for art sub planning, so don’t miss this one!