Association Montessori Internationale (AMI) has a free set of cards for leaf shapes here (illustrations) and here (photos).
There are actually lots and lots of leaf shapes — some with just minor differences between them — but the following are a few of the most common:
The worksheets below are designed to help students master the different shapes of leaves, but don’t forget to go out into your garden / backyard / nearest forest and check out the leaf shapes on actual, real-life plants!
Note on the Worksheets
You can reduce the size of the worksheet by zooming out your browser screen. For Windows users, scroll down the mouse wheel while pressing the Ctrl key in your keyboard. If there are any errors/glitches, just refresh and try again.
You can download a free printable version of this worksheet here: Montessori Leaf Shapes Worksheet 1 (PDF)
You can download a free printable version of this worksheet here: Montessori Leaf Shapes Worksheet 2 (PDF)