Unofficial list of 3rd party boards support urlsAdafruit: https://adafruit.github.io/arduino-board-index/package_adafruit_index.json Adafruit AVR Boards (Flora, Metro, Trinket, Pro Trinket, & Gemma) Adafruit SAMD Boards (Feather M0) TeeOnArdu USB MIDI support for Leonardo & Micro arcore USB MIDI support for Leonardo & Micro Adelino: http://adelino.cc/package_adelino_index.json Adelino is a dual-microcontroller development board based on ATmega3
