Hi @simplythebest,I am not sure exactly what you are looking for as a virtual keyboard connected to an eye tracker would still have to work in the exact same way as the google (or Windows) virtual Keyboard.
I found an article regarding a specially created KB @ https://ieeexplore.ieee.org/document/7464272
Perhaps the developers would be willing to share the code with you.
Otherwise, I am afraid I have no further suggestions for you in this regard unless you would clarify the intentions.