I make a lot of small pixel art for RPG Maker 2003. I made this brush while experimenting with ways to make trees faster.
The three brushes at 100% view:

At 200%
Top to bottom:
- 3.3px Leaves
- 4.7px Leaves
- 6px Spray
With a little clean up, you can get some nice looking tree tops & bushes from them:
1

Or you can make piles of leaves for autumn areas!

Feel free to use them for a game or whatever else you make. :)

Leaf Brushes