I've learned to love Procreate, and for the most part I use brushes straight out of the box. But there are a few that I've created or modified that I find useful, especially a couple of blenders that match the behavior of my Photoshop brushes. Here they are: (The titles are links)
The NEW Round brush: I really like Procreate's "Round Brush, but I like something a little more forgiving for smooth gradients but that still gets that nice hard edge. I occasionally adjust the spacing to get a rougher stroke and easier blending.
Rough Inking: Great for flat areas with rough edges.
Rough Ink Small: Has a smaller size range, great for outlining the edges in a similar style to the rough ink pen.
The Flattened Photoshop. Sometimes you want that digital feel with the control that a brush with flattened roundness gives you. This brush does a pretty good job!
Palette Knife. This brush doesn't have the "Height" texture controls that I like from Photoshop, but it gives me 80% of what I'm looking for out of a digital palette knife.
The Occlusion Brush. A gradient brush with the falloff of ambient occlusion, great for quickly tucking contact shadows up against edges.
The Smudge Nice. Very similar in behavior to my Photoshop smudge, but it follows the "Azimuth" of the stylus.
The Dry Blender. Like my dry blender from Photoshop, use as a smudge tool.