EasyBlend is a shader which allows you to set a custom blending mode for your canvas item. Included are many of the blending modes you will find in common image editors.
The blend is applied based on a 2d lookup table per color channel in the form of an input texture. This allows plenty of blends in addition to the ones shown, such as colored fogs and underwater effects.
Update 1.1 (18 Sep 2018): Added an "Enabled" property and fixed the default intensity to 1.0.