The Adafruit Feather are a complete line of development boards from Adafruit that are both standalone and stackable. They’re able to be powered by lipo batteries for on-the-go use or by their micro-USB plugs for stationary projects. Feathers are flexible, portable, and as light as their namesake.
Another nine pinouts of these fantastic cards:

Feather 32u4 Fona
Feather M0 Express
Feather M0 LoRa
Feather M0 RFMxx
Feather nRF52
Huzzah ESP8266
Wiced WiFi
Feather 32u4 RFMxx
Feather 32u4 LoRa