ATmega32U4 Mega32U4 5V 16MHz Module Pro Micro USB Controller Board for Arduino Nano Mini Leonardo ATMEGA32U4-AU with Bootloader: Amazon.com: Industrial & Scientific
Pro Micro & Fio V3 Hookup Guide - SparkFun Learn
TENSTAR ROBOT Pro Micro With the bootloader Black/Blue ATmega32U4 5V/16MHz Module controller Mega32U4 leonardo for arduino|robot control|robot minipro micro - AliExpress
SOLVED] Problem to upload to Pro Micro - Microcontrollers - Arduino Forum
Amazon.com: HiLetgo 3pcs Pro Micro Atmega32U4 5V 16MHz Bootloadered IDE Micro USB Pro Micro Development Board Microcontroller Compatible to Arduino Pro Micro Serial Connection with Pin Header : Electronics
Pro Micro & Fio V3 Hookup Guide - SparkFun Learn
Reinstall bootloader for an Arduino Pro Micro?
Eagle Library for Arduino Pro Micro - General Electronics - Arduino Forum
Pro Micro with The bootloader Black/Blue ATmega32U4 5V/16MHz Module Controller Mega32U4 Leonardo Suitable arduino-Micro USB 3-18V - Newegg.com
Arduino Pro Micro keeps disconnecting while uploading code - Avrdude, stk500, Bootloader issues - Arduino Forum