Amazon.com: hejhncii CJMCU Micro Card Badusb USB Virtual TTF Memory Keyboard ATMEGA32U4-Module for Arduino-Leonardo R3 : Electronics
KeyBoh Is an Open Source Arduino Leonardo Shield for Making Custom USB Keyboards - Hackster.io
Amazon.com: SunFounder FruitKey USB Keyboard DIY Starter Kit Gamepad Control Handle DIY Computer Keyboard, Worked with PC Mac OS X Raspberry Pi for Arduino Uno R3 Leonardo : Electronics
Arduino 4x4 Keypad Interfacing With Arduino Uno | Arduino
Turn your ProMicro into a USB Keyboard/Mouse - SparkFun Electronics
Arduino Keyboard Is Gorgeous Inside And Out | Hackaday