Creating 3D LUTs

As of, erm, 5.2? Fusion has supported 3D LUTs, in the image view and on the flow, natively (I think Rising Sun had a plugin for that before then). These go beyond ordinary (1D) LUTs and allow you to do more than simply adjust colour intensities, but to map colours to completely different colours, like making the image sepia, or changing all the chartreuse pixels in your image to a sort of pinky-russet.

In fact, pretty much any non-spatial colour correction can be done with a single 3D LUT, limited only by the range and accuracy of the LUT. They're fast too, at least when accelerated by modern GPU hardware. The catch; you had to find your own 3D LUT files, somewhere.