Here is the latest revision of the Adafruit Feather board pinouts:

Feather 32u4 Fona
Feather M0 Express
Feather M0 LoRa
Feather M0 RFMxx
Feather nRF52
Huzzah ESP8266
Wiced WiFi
Feather 32u4 RFMxx
Feather 32u4 LoRa
Feather 32u4 Basic Proto
Feather 32u4 Adalogger
Feather 32u4 Bluefruit
Feather M0 Basic Proto
Feather M0 Adalogger
Feather M0 Bluefruit