Reuleaux
An HSV-like color model similar to one Steve Yedlin, ASC has demonstrated online.
Installation | Overview | Derivation | Tooling
A number of tools are included. Ideally they'll provide a launch pad for others to create their own.
Note that BlinkScript was made available to Nuke Non-commercial users in version 14.0v3, so the BlinkScripts will work there. Regardless, prefer the .nk version of the model itself.
Massive thanks to project co-author calvinsilly, whose efforts this model would not exist without.
Check out a similar model by Juan Pablo Zambrano, which has two chroma normalization modes.