Change pixels color and coordinates doing several operations, can generate spritesTheses modifiers are kind of the same than the stylize filters of Photoshop. No more, no less. They maybe a little dull sometimes but they do the job like Bruce Willis. Action movie style, rough and dirty !
Anyway, in combination with masks or meta modifiers (go check into the Utility Modifiers section) they can do some awesome effects.
Ambient Occlusion - Adds screen-space ambient occlusion
Chromatic Aberration - Lens chromatic aberration effect
RGB Separate - Separate Red, Green and Blue layers
Sparkles - Generate sparkles on top of the image
Pixelate - Pixelate image
Sharpen - Sharpen effect using image samples
Emboss - Emboss effect using image samples
Sobel - Draw lines on contrasted area of the image using edge detection
Tiles - Turn the image into an assembly of tiles