Mini USB ATmega32U4 Pro Micro 5V 16MHz Board Module for Arduino/Leonardo ATMega 32U4 Controller Pro-Micro Replace Pro Mini : Electronics - Amazon.com
Arduino Leonardo Pinout, Schematic and Specifications in detail
ATmega32U4 Pro Micro USB 5V 16MHz Board Module for Arduino Leonardo ATMega 32U4 Controller Pro-Micro Replace Pro Mini with Pins: Amazon.com: Industrial & Scientific
Arduino Leonardo with Headers - DEV-11286 - SparkFun Electronics
Arduino Leonardo Pinout
Step by Step Guide to the Arduino Leonardo : 7 Steps (with Pictures) - Instructables
Mind doing some pin remapping for other 32u4 boards? (Arduino Leonardo R3) · Issue #2 · bootsector/XInputPadMicro · GitHub