This nice package provides you with 25+ robust and convenient utilities to manipulate Texture2D assets. Change textures on pixel level right in runtime, to achieve a lot of complex and useful effects.
Drastically extends Unity's texture functionality, bringing such features as:
• Apply masks, Boolean operations
• Rotate, scale, mirror, expand, crop
• Contrast, brightness, HUE, saturation
• Colorize, grayscale, negative, color diapason
• Invert transparency, make color transparent
• Stroke, etc
Small DEMO is here