AutoDraw fun simple drawing games. https://www.autodraw.com/
Toy Theater- http://toytheater.com/category/art/
Silly Animal Virtual Assemblages https://switchzoo.com - may be a fun precursor to a drawing
Digital Coloring Website http://scrapcoloring.com/ - for younger kids, K-2ish
Art Detective https://www.tate.org.uk/kids/games-quizzes/art-detective - requires flash