9 pin to USB Dual Atari Joystick, Paddle, and Driving Adapter by iCode, DB9 Ports, Plus Edition : Video Games - Amazon.com
Retro Joystick CPC+/GX4000 Adapter
USB Joystick Adapters – breadbox64.com
Amazon.com: JoFong 9 Pin Controller Extension Cable for Classic Retro Game Consoles AV 620, HD 621, HD 821 Plug and Play Wired Video Game Controller Gamepad Extension Cable 5.8ft 2 Pack (cable-new-abc) :
Making a 9 Pin Joystick Cable (for Sega Genesis, Commodore 64, ColecoVision, Atari, etc.) - YouTube
9 pin joystick port to USB - Unboxing and review - Retro Adapter - YouTube
USBJoy2.0E adapter - Extended Version. Connect your Atari Amiga C64 joystick to PC! Develop your own usb device! - Polish electronics for 3D printers, CNC, robotics, retro computers
9 pin to USB Joystick adapter for A500 Mini, Raspberry Pi, Mister, PC, Android Box – TruMouse.com