Also called adjustment layers. 

• Solid Colour
• Gradient
• Pattern
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• Brightness/Contrast
• Levels
• Curves
• Exposure
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• Vibrance
• Hue/Saturation
• Colour Balance
• Black & White
• Photo Filter
• Channel Mixer
• Colour Lookup
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• Invert
• Posterize
• Threshold
• Gradient Map
• Selective Colour