Default brushes are actually not the devil.
I created all of these textures using various brushes within the “assorted brushes” category in Photoshop with settings like size and angle jitters and scattering applied and opacity controlled by pen pressure. Any brush on Photoshop can be used to create an interesting and unique texture if you use it right, even the dreaded default brushes.
I actually didn’t think the star would work when I started it, but it ended up looking like watercolor. Is that not the coolest thing?