File>Preferences>Setting
http://arduino.esp8266.com/stable/package_esp8266com_index.json

Tools>Board>esp8266>Generic ESP8266 Module
esp8266

Library Manager
ESP8266 and ESP32 OLED driver for SSD1306 display

Additional
Adafruit SSD1306
Adafruit GFX Library
Adafruit BusIO

