For Grease Pencil sculpt modes each brush type is exposed as a tool, the brush can be changed in the Tool Settings. See Brush for more information.
Grease Pencil sculpt tools:
Some Object Mode are also present.
Select or moved.
Eliminates irregularities in the area of the drawing within the brush’s influence by smoothing the positions of the points.
Increase or decrease the points thickness in the area of the drawing within the brush’s influence.
Increase or decrease the points transparency (alpha) in the area of the drawing within the brush’s influence.
Add noise to the strokes in the area of the drawing within the brush’s influence by moving points location in a random way.
Used to drag a group of points around. Unlike the other brushes, Grab does not modify different points as the brush is dragged across the model. Instead, Grab selects a group of points on mouse-down, and pulls them to follow the mouse. The effect is similar to moving a group of points in Edit Mode with Proportional Editing enabled.
Moves points in the direction of the brush stroke.
Twist the points in counter-clockwise (CCW) or Clockwise (CW) rotation.
Pulls points towards the center of the brush. The inverse setting is Inflate, in which points are pushed away from the center of the brush.
Adds copies of the strokes in the clipboard in the center of the brush. You have to copy the selected strokes you want into the clipboard with Ctrl-C before using the tool.