Here is a list of all of my free Photoshop brush sets that are high resolution. This means that the average Photoshop brush size is larger than 1200 pixels (in most cases here, much larger).

Aurora Borealis Photoshop Brushes
Beach Sketches Photoshop Brushes
Distressed Photoshop Brushes
Dripping Photoshop Brushes
Earth Friendly Vectors Photoshop Brushes
Fairy Wings Photoshop Brushes
Flower Vectors Photoshop Brushes
Foliage Swirls Photoshop Brushes
Glowing Bugs Photoshop Brushes
Graduation Sketches Photoshop Brushes
Grungy Dirty Photoshop Brushes
Hair Strands Photoshop Brushes
Light Beams Photoshop Brushes
Light Swirls Photoshop Brushes
Makeup & Face Sketches Brushes