This is the big daddy of Pro Minis. I have a bunch of these in my Arduino bin and in my biggest project, the Maple Syrup machine room that I call the SapMaster.

This board uses a micro-USB connector, ATMEGA2560, and a CH340G USB to serial chip.

This is an extremely capable chip. I pair it with an ESP32 and a dual FRAM board in the SapMaster controller.