"Textured Painting - Natures Paint Brushes" This is not just art, but art in nature! Go on a nature walk to gather 'schtuff!' Then use what you gather to create art or As art!
Lovely autumn activity - find the tree that matches the leaf. From A Mom with a Lesson Plan (",) (autumn activities for kids)
Easy Bug Hotel for Kids to make - Red Ted Art. If carefully supervised secateurs and a penknife / cutting block (keep fingers behind the knife) make it an older child's craft.