Smooth Lineart Pen: I use this for my sticker designs usually because it has very little line variation.
Dry Ink Pen: My favorite brush, used in most of my art, lightly textured.
Scribbly Dry Ink: Variation of Dry Ink Pen, if I sketch with this I tend to clean it up and keep it as lineart. Allows for more loose lines.
Better Pencil: Similar to Procreate default pencil brushes, but more smudgy, soft, and buildable. Allows me to simulate how I draw on paper.