Adafruit has tested WebUSB and TinyUSB with Microchip (formerly Atmel) ATSAMD21 and ATSAMD51 based processor boards sold by Adafruit. The Nordic nRF52840 is also supported by TinyUSB.
This project will use the ATSAMD21-based Adafruit Circuit Playground Express (CPX). This board has sensors, buttons, and NeoPixel LEDs to provide an excellent test platform. USB connectivity is via a micro-B USB connection.
The Circuit Playground Express supports a number of programming methods including CircuitPython, Microsoft MakeCode, and Arduino.
Adafruit has developed demonstrations of WebUSB and TinyUSB in Arduino as of the publication of this guide.