Create a Joystick Using the Arduino Joystick Library 2.0 : 12 Steps (with Pictures) - Instructables
DIY Arduino Buttonbox | Page 5
Turn your ProMicro into a USB Keyboard/Mouse - SparkFun Electronics
Joystick-button shield - TavIR WebShop
Pedal & Button Controller (eng) — OpenSimHardware
Arduino 56 Button Joystick 737 Gear Control - YouTube
Precision USB Joystick Controller BU0836
Arduino Game Controller - Hackster.io
3*4 DIY Matrix for Buttons [Solved] - Product Design - Arduino Forum
MCDU and OEM Equipment Interfacing (Joystick Board) | Soarbywire
DIY « Viking's blog
Using the joystick with Arduino
Might have bit off more than I can chew. 56 buttons, 5 rotaries and 2 joys - Project Guidance - Arduino Forum
I made a gaming control panel using an Arduino Leonardo to play simulators. Currently using it for DCS World, but it should work in most games just like any joystick / gamepad.
Pro Micro Button Box with Matrix - Code Help - Programming Questions - Arduino Forum