I haven't seen anyone say anything about this yet, but if you have two ColorCorrectionEffects both set to -1 you can invert all the colors in workspace!
However interestingly, this doesn't apply to white or black. So instead you just get funky colors. Interesting effect. Stacking this effect (more than two ColorColorrections) has the same effect of boosting this inverted saturation.
(also if this is the wrong category sorry i thought it fit best)