Hey Auntjemimma, hey all,
here is that list of touch displays that work with the Onefinity Controller.
As the Onefinity Controller contains a Raspberry Pi, any HDMI (or DVI-D or DVI-I which is compatible to HDMI) computer monitor will do, and of course any USB input device like keyboards, mice, trackballs (I like trackballs on CNC controllers. Unlike mice they need no space on a surface and are also very practical when you are standing, since they also work when mounted on a vertical surface 
) e.g. the Kensington Orbit with Scroll Ring (usable for both right/left-handers)
The list of monitors above is for Touch Monitors, the touch device inside the monitor is an USB input device too and has to be connected independently of the display part of the monitor.
Don’t choose too small touch display
What I think about Touch screens is that on a CNC controller or a similar machine, one should always think of “how thick is my index finger?”, and choose a monitor size where the buttons of the virtual display keyboard and the buttons fo the Jog Pane are bigger than your finger tip. That would mean that the monitor to choose should be rather large. If it’s too small, you press wrong buttons too easily. For that reason, I never thought of buying the touch monitor Onefinity offered (it is for very, very small people and you should not have presbyopia (but people >45 usually have) )