Arduino (Pro) micro as a USB-MIDI device (MIDIUSB library) - and change its name to whatever you wan - The Nerd Musician
DIY USB Midi Controller With Arduino: a Beginner's Guide : 10 Steps (with Pictures) - Instructables
Mini USB-MIDI to MIDI – Simple DIY Electronic Music Projects
How To Program The Pro Micro (atmega32u4) As A USB Gamepad Controller With Arduino - tinkerBOY
Midi controller - 5 Pots - Pro Micro - HELP (newbie) - Project Guidance - Arduino Forum
Tzt Pro Micro Atmega32u4 5v 16mhz Replace Atmega328 For Arduino Pro Mini With 2 Row Pin Header For Leonardo Mini Usb Interface - Integrated Circuits - AliExpress
The $8.04 USB MIDI Breath Controller - Hardware - Zynthian Discourse
$10 USB MIDI Host (for MIDI controllers) - MOD WIGGLER