Voxengo has updated its dynamic parametric equalizer plug-in, GlissEQ, to v3.9.
This version implements the following changes:

• Added Pro Tools 12+ AAX-64 support.
• Control points can be now added by simple dragging.
• Made the summary EQ curve thicker.
• Added a set of predefined static spectrums.
• Fixed erratic behavior of the "Low-Pass 6" filter when its frequency was set above Nyquist.
• Fixed an issue when two instances used the same export slot.
• Implemented color scheme editor with load and save functions.
• Added "Brown", "White" and "Cyan" color schemes.
• Redesigned the infrastructure controls.
• Made bottom group selector switchable.
• Added switchable visual colorization.
• Made internal channel names start at "C" to reduce confusion with the A/B comparison buttons.
• Made user interface scale switchable without host reload.
• Added 90%, 110% and 150% visual scales.
• Added "RT Sigma" analyzer type.
• Added "Spectrum Offset" display modes.
• Reduced plugin file size considerably for faster loading.
• Reduced the overall memory consumption.
• Bypass switch's state is now saved with the project.

An oldie but a goodie. This was the first plugin I'm aware of that offered multi-track spectral comparisons to aid in complementary equalization.
 
It used to be a favorite and I've dutifully kept it up-to-date even though it no longer gets any use. The problem I had with it is that it's a dynamic EQ but you have little control over the dynamic action. Meldaproduction's MDynamicEQ, by contrast, gives you total control over every parameter for a more predictable result.
 
But I'm gonna have to dust off GlissEQ again and see if it still has something to offer.