Brush Tool (B): This tool works like a conventional paint-brush and draws soft strokes.
Bump Tool: This is one of the liquifying tools in Pixelmator. It moves pixels away from the centre of the brush area as you click or drag on the image. This effect is useful when you want to simulate a bloated effect.
Burn Tool: This tool darkens image areas by painting over them.
Canvas Size (Command-Option-C): The Canvas Size command allows you to adjust the entire editable area of an image. Increasing the editable area adds more space; decreasing the area crops the image.
Clipping mask (Command-Option-G):Turning a layer into a clipping mask lets you use the objects on the underlying layer as a mask.