There are many many controllers which work as expected with PF and as such work perfectly.
I only guess, that everyone defines 'perfectly' in a slightly different way
The ProppFrexx GPIO interfaces for example are NOT designed to replace the entire graphical user interface and 'mirror' all its functionalities! If you want this I can only say no, that is not possible and not even intended - the controller however still works perfectly.
All available control-commands, which can be send to ProppFrexx from an external device are listed in the Appendix of the User-Manual.
The related Voice-Tracking commands start with "VT_...", e.g.:
MAIN_SHOW_VOICETRACKING : Opens the VoiceTracking window
VT_REC_BUTTON : Emulates a REC button click if the VoiceTracking window is shown
VT_FADESTOP_BUTTON : Emulates a FADE/STOP button click if the VoiceTracking window is shown
VT_NEXTENTRY_BUTTON : Emulates a NextPlaylistEntry button click if the VoiceTracking window is shown
VT_NEXTPLACEHOLDER_BUTTON : Emulates a NextPlaylistPlaceholder button click if the VoiceTracking window is shown
...and many more...
As such, ANY external MIDI device, which can send standard midi messages can be used to trigger such commands.
However, there is for example no control-command available to down mix an entire playlist into a single audio file and save it to a certain file and format. This because downmixing a playlist involves the selection of the format and entering the target filename and option. As such, a single button command makes no real sense. Here is a right-click with the mouse and entering the filename via your keyboard needed - a task which can not be much more simple.