Getting Started with ESP8266 NodeMCU Development Board| Random Nerd Tutorials
Amazon.com: WLAN WiFi Internet Development Board D1 Mini NodeMcu Lua 4M Bytes Development Module Base on ESP8266 ESP-12F for Arduino Compatible with WeMos D1 Mini (10PCS) : Electronics
ESP8266 Node MCU board specifications and pins descriptions. Frequently asked questions related to WI-FI board esp8266 node MCU
Nodemcu ESP8266 Pinout, Features, and specifications
Espressif ESP8266 Serial ESP-01 WiFi Module - Datasheet Hub
Things You Should Know Before Using ESP8266 WiFi Module - Hackster.io