When I am teaching contour line drawing to my fifth graders, I like to use still life set-ups that include objects familiar to the students. That age group is not that far from the age of sleeping with stuffed animals, so I find that they feel comfortable trying to draw them.
I put together a small collection of public domain photos in PowerPoint that would work nicely as still lifes for elementary drawings. You might use them all at once in a lesson or save them to show individually as warm-up exercises.
If you would like to have a copy of the PowerPoint, all you have to do is download it for free.