Nikolas Konstantakopoulos has introduced Geff 1.0 (http://www.grannysaudio.com/geff), a virtual guitar rack for macOS. It’s a standalone audio effects application to use with your guitar like you would a collection of stompboxes.
Geff includes a variety of effects. You can add as many effects and re-arrange them as you like. It offers handling for adding and rearranging effects, using MIDI learning to map almost any parameter of its effects to your MIDI controller.
Geff is separated to three components, Header or Input component, Middle or Effects, and the Footer or Output component. As their names suggest, the Input component manages the audio input, the Effects create and includes the used effects, and the output manages the audio output. In addition, Geff has the ability to map your MIDI controller to almost any of its parameters.
Geff requires macOS 10.6.6 or later. It costs $19.99 and is available worldwide exclusively through the Mac App Store in the Music category.