Round versatile brush works good for sparkles and incidentally, with the right settings, it works for grass and leaves too.
This is my first brush. I wanted to try the assets challenge.

The sparkles on the dress, the leaves of the tree, even the grass and tree bark were made using this brush. The particle size is adjustable, so you can make small as well as large sparkles.
Some of you may have noticed that the particles in the grass are not round. This can be achieved using the thickness slider. Brush density is also adjustable, in case you need faint sparkles.
You can use a contrasting color for the sparkles, it can have a nice effect. Especially when used tastefully.

Make the particles small and the brush big, and you can make a quick night sky.

I hope you find this useful.
-ShrimpPhish-