I get all my free brushes from the procreate website under “resources” you can even filter just the brushes
https://procreate.art/discussions/10 Peggy dean, kohler, and Maggie nurse or nurse something...are my favorite for calligraphy brushes. I am an actual calligrapher and lettering artist and had made one perfect but after last update it’s not the same, no matter what I tried. I have noticed though if you play with tilt and pressure you can get it pretty close