Parametric-brushes
From GIMP GUI Redesign
Contents
Parametric Brushes
Current Editor
Editor with irregular polygon shape
Contextual Menu of Vector Brushes on the dialog list
Edit Vector Brush > open vector brush editor with the current brush. --- New Vector Brush > open the editor. Duplicate Brush > = Copy Brush Location > = Show in File Manager > = Delete Brush > = --- Refresh Brushes > =
I would also suggest adding the shape of irregular polygon into the settings of parametric brushes (Zabadal).