HID keyboard with toggle switch - Project Guidance - Arduino Forum
USB Tastatur Chip IC Modul HID Große Tastatur Kann Verwendet Werden als Spiel Konsole - AliExpress
V-USB - A Firmware-Only USB Driver for Atmel AVR Microcontrollers
GitHub - houkanshan/arduino-bt-hid-proxy: Bluetooth HID proxy is implemented using Arduino. Make a Bluetooth keyboard or mouse (WIP) work in BIOS or device without BT stack (e.g. TMK USB to USB Converter)