MakerFocus Wemos D1 Mini WiFi Module with 18650 Battery Slot ESP WROOM
Power Management | Adafruit Feather HUZZAH ESP8266 | Adafruit Learning System
Amazon.com: MakerFocus WiFi Test Tool DSTIKE WiFi Deauther Watch V3 ESP8266 Programmable Development Board Built in 800mAh Battery with OLED Display, Laser, Wristband and 3D Printing Case for Ar duino NodeMCU :
OCESTORE Mini D1 Module Wemos D1 ESP8266 with Battery Slot ESP WROOM 02 Motherboard Compatible with Node-MCU
Seven Pro Tips for ESP8266 : 9 Steps (with Pictures) - Instructables