ESP8266 NodeMCU (Arduino compiler) Pins. Now with WeMos D1 Mini! – www.holdentechnology.com
Getting Started w/ NodeMCU ESP8266 on Arduino IDE - Arduino Project Hub
For Wemos Mini D1 ESP8266 ESP32 ESP 32S WIFI Bluetooth CP2104 Development Board Module For Arduino With Pins|development board|wifi modulemodule bluetooth - AliExpress
GPIO pins of ESP8266 and How to use efficiently -IoTbyHVM
ESP8266 Pinout Reference: Which GPIO pins should you use? | Random Nerd Tutorials