Arduino

• LED Matrix editor
  
• Adafruit NeoPixel Überguide
  
• Binary to hex editor
• An open source icon set with 223 marks
• https://io.adafruit.com/phobic/profile
• Arduino libraries

ESP8266

• Using the ESP8266 WiFi Module with Arduino Uno publishing to ThingSpeak
  
• A Beginner’s Guide to the ESP8266
• USING ESP-01 AND ARDUINO UNO
• ESP8266 Temperature / Humidity Webserver
• ESP8266 – Easiest way to program so far (Using Arduino IDE)