nMask is gizmo for creating masks from flat colors, it's working on principe of color differences.
nThreshold Gizmo converts grayscale or color images to high-contrast, black-and-white images.
Color matte for Red, Green, Blue, Cyan, Magenta, Yellow, Black, White and where there is any colour information.
Fill Light is a simple and effective image tone mapping tool. Works on any type of image: 8bit, 16bit, 32bit (exr, hdr).
Extract luma or Chroma from your plate.
PAF_Matchit_BW semiautomatically match the Blackpoints and Whitepoints of a FG image based on the BG image.
Simple gizmo that mimics the functionality of the Photoshop Levels tool
Absolute Luminance Calibration of Panoramic HDRI Images & Analytical Light Sources Creation
Similar to Photoshop's photofilter, for quickly changing the color balance and color temperature.
Converts PhotoShop Curves into Nuke ColorLookup