Krita

Input

• Stylus Button: Drag Canvas
• Shift Stylus Button: Rotate Canvas
• 5: reset rotation to north
• Control Stylus Button: Zoom Canvas
• Control Tap: Select Color
• Back Stylus Button: Pen Wheel
• F: Fill Tool
• B: Brush Tool
• Shift Tip Drag: Brush Size
• Transform -> Control Rotate: Rotate in 3D Space
• Control M: Non-Destructive Mirror
• Shift Backspace: Fill Layer (or selected area) With Color

Interface

• Alpha Lock is to paint on pixels that already have paint in the active layer. (shift backspace will only fill painted pixels, also)
• Inherit Alpha applies the alpha of parent layer to this layer (this layer can have more painted pixels, but they will not be visible with Inherit Alpha turned on).