Free with Procreate!
Find it in the Brush Library under Painting
If I'm drawing really wide letterforms or shapes, I will sketch with this brush first to make sure the width stays consistent. In the example below I used the Flat Brush in the base sketch which made it much easier to keep the width of the pencil illustration even and uniform.
Keep in mind that this brush is pressure sensitive, therefore it will appear lighter or darker, depending on how much pressure you apply.