Amazon.com: The C64 Mini +1 Additional C64 Joystick : Video Games
USB adapter for DB9 joysticks - (Amiga,Atari,Commodore,C64,MSX,SMS,emulators...) | eBay
USB Joystick Adapter from Retronic Design on Tindie
C64 Joystick Adapter - Share Project - PCBWay
USB adapter for DB9 joysticks - (Amiga,Atari,Commodore,C64,MSX,SMS,emulators...) | eBay
USB C64 Joystick adapter (for emulator) - Commodore Remix
USB joystick adapter for 9 Pin Atari joysticks - YouTube
9 Pin Joystick to USB Adapter
Best Amiga Atari ST C64/C128 Commodore Mouse Gamepad Joystick USB adapter TOM+ | eBay
USBJoy2.0 - adapter. Connect your Atari Amiga C64 joystick to PC! Develop your own usb device! - Polish electronics for 3D printers, CNC, robotics, retro computers