You can add brushes to Procreate by downloading .brush files onto your iPad, and then "sharing" them to Procreate.

As it has done several times in the past, Apple is offering a free download of a popular iOS app via the Apple Store app. This time, the company is offering popular sketching app Procreate for iPhone ...

Procreate Pocket ($4.99 on App Store) is the iPhone rendition of the popular Procreate drawing app for iPad. Version 2.0 of Procreate Pocket was just released today, and it’s basically a brand new app ...