As a Freebie we provide the basis of our upcoming Frequalizer. It features frequency response plots, six filters. You can choose of a variety of filter types, including Shelf, Peak and Notch filters. There are shortcuts to solo each filter and to activate and deactivate each filter.
The Frequalizer features six filters, that can be switched on and off and be soloed individually.
Latest Version, running on Mac OSX 10.9 and above. The installer contains the plugin for AU, VST, VST3 and AAX: