Wide Paint Brush
I'm not sure if these are standard brush sets in PS, but check and see if you have sets called "Assorted Brushes," "Dry Media Brushes," or "Thick Heavy Brushes." Some of the brushes in those sets render a natural looking brush stroke.
|Orange-tip Butterfly by anisah|
from Nature's Colour Palette
|Windswept juniper by Kreber|
from Wind power