Random Nerd Tutorials | Learn ESP32, ESP8266, Arduino, and Raspberry Pi

Link: Random Nerd Tutorials | Learn ESP32, ESP8266, Arduino, and Raspberry Pi: "Random Nerd Tutorials helps makers, hobbyists and engineers build electronics projects. We make projects with: ESP32, ESP8266, Arduino, Raspberry Pi, Home Automation and Internet of Things. If you want to learn electronics and programming, you're in the right place."

I just came across the linked catalog of free tutorials. Looks like it could be very useful! Arduinos, Raspberry Pis, and more.