A default Procreate brush, the Shale Brush is perfect for drawing, blending, and erasing. It can accomplish so much that I use it for pretty much everything. It is without a doubt my default brush. Its only weakness is that it doesn’t taper very well, so when I draw or color hair, I use the free Gouache-ish Brush.
Shale Brush x Gouache-ish Brush
The ultimate combo. Unexpectedly, the Shale Brush is magnificent for blending/smudging. Combined with using the Gouache-ish brush for drawing, filling in, amd smudging the pointy parts (hair), art with a really nice texture can be made.
My examples mostly include anime character fan art, but hopefully it displays well the blending abilities of Shale Brush.