MacroFusion fuses multiple photos into one with greater DOF (Deep of Field) or DR (Dynamic Range). It can be useful for macro lovers or landscapers.
Simulate HDR is a plugin for The GIMP that creates two layers from a single image simulating an underexposed and an overexposed shot, creating a High Dynamic Range image. It can create a tone mapping layer to compress the color range of the image.
An application to annotate screenshots.
A command-line filter converting to or from a CSV stream.