This set of high-resolution leaf Photoshop brushes is ideal for sketching leaves for creating organic textured backdrops. Seven standalone leaf pictures with exquisite details and textures are included. They’re free to use for personal and commercial purposes, but you must credit them according to the Creative Commons terms, which you can see on the Brusheezy site.
jschill is the designer.
Usage: Personal and commercial use are both free.
Brusheezy offers a free download.