Natural Drawing and Painting Media Brushes: Photoshop Brushes
They include some basic brushes I made in Photoshop in the following styles: Pencil, pen, marker, oil pastel, gouache and splatter.
Also work in the latest version of Clip Studio Paint
These will work if you import the ABR file into the sub tool palette, you may have to change some settings for stroke spacing and watercolour edge on some of the brushes. Read about how to do that here: http://theartsquirrel.com/wiki/import-photoshop-brushes-into-clip-studio-paint/