Amazon.com: Gateron MX Switch 3 pin and 5 pin Transparent Case Black Red Green Brown Blue Clear Switches for Mechanical Keyboard Cherry MX Compatible : Electronics
Stylish 22 key keypad with a serial (9 pin D) connecter : KBC-22S : The Keyboard Company
tinkerBOY IBM Terminal Keyboard (240 Degree, 5-pin DIN) to USB Converter with Vial QMK Firmware - tinkerBOY
DIN connector - Wikipedia
NEW SEALED Logitech 920-006340 Wired 30-Pin Keyboard for iPad | eBay
What IBM keyboard is this? - deskthority
8-pin mini DIN keyboard to work with PS/2 (6-pin mini) : r/MechanicalKeyboards