ESP8266 List of firmwares
General
Nodemcu
https://github.com/nodemcu/nodemcu-firmware
Micro Python
https://github.com/micropython/micropython
Home Automation
ESPEasy
https://github.com/letscontrolit/ESPEasy
Sonoff-Tasmota
https://github.com/arendst/Sonoff-Tasmota
ESPurna
https://github.com/xoseperez/espurna
ESPHome
https://github.com/esphome/esphome
Other
ESP-LINK: Wifi-Serial Bridge w/REST&MQTT
https://github.com/jeelabs/esp-link
Frankenstein
https://github.com/nekromant/esp8266-frankenstein
Ka-Radio
https://github.com/karawin/Ka-Radio
ESP8266 deauther
https://github.com/spacehuhn/esp8266_deauther
ESP WiFi repeater
https://github.com/martin-ger/esp_wifi_repeater
Mongoose OS
https://github.com/cesanta/mongoose-os
Audio Reactive LED Strip
https://github.com/scottlawsonbc/audio-reactive-led-strip
HTTP IR Blaster
https://github.com/mdhiggins/ESP8266-HTTP-IR-Blaster
ESP3D - 3D Printer control
https://github.com/luc-github/ESP3D