That’s a massive clue as to what the driver IC is :D
I don’t have any documents I’ve written, but pretty much every part we’ve used (apart from Dial, Slider and Joystick) is standard with available datasheets, and has been used elsewhere on one of our products. Enviro pHAT, for example, has “Weather” and “Colour” onboard IIRC.
Matrix and Number are the same chip as used on Scroll pHAT (IIRC) and Micro Dot pHAT.
Touch is the same chip family as on Display-o-Tron HAT, Touch pHAT.
Most of the answers are in one Python library or another, and getting something like Matrix or Number up and running would be challenging, but especially rewarding. Neither of them do anything special, mind, like the bonkers insanity you’ll find on Micro Dot pHAT.
(Trivia: I actually prototyped a two-digit Micro Dot pHAT with an unpopulated Flotilla Matrix prototype PCB before moving onto the 6-digit pHAT layout)