If you are looking for an audio plugin that can work as a virtual master keyboard, you might want to explore the features MidiMaster puts at your disposal, which is something you can do provided that you connect it to your host, more specifically between the Midi In and the VSTi or VST instrument set you are working with.
With the help of MidiMaster, you can have your keyboard split into two main areas, one corresponding to the highest note, the other to the lowest. It is also worth pointing out that, for each of these zones, you can set the desired volume level, transmitting midi channel, the transpose, as well as the Program Change message you want to be conveyed on the channel.
Nevertheless, disabling this feature is also an option, which means you can enjoy the aforementioned capabilities on the whole extension of the keyboard.
Other than that, what MidiMaster can do for you is help you associate sliders, knobs, and the switch with CC messages, which enables you to migrate them from the real master keyboard.
Last but not least, users may want to know that the virtual master keyboard could come in handy especially in live performances since its 128 settings can be loaded up in real time, ensuring a high degree of flexibility.